Tag LLVM

Write an LLVM Pass

In this post, I will show how I write an...

01 Mar 2017

Tag Hash Table

X Of A Kind In A Deck Of Cards Problem

LeetCode 914. In a deck of cards, each card has...

01 Oct 2022

Word Subsets Problem

LeetCode 916. You are given two string arrays words1 and...

01 Oct 2022

Vowel Spellchecker Problem

LeetCode 966. Given a wordlist, we want to implement a...

01 Oct 2022

Vertical Order Traversal Of A Binary Tree Problem

LeetCode 987. Given the root of a binary tree, calculate...

01 Oct 2022

Verifying An Alien Dictionary Problem

LeetCode 953. In an alien language, surprisingly, they also use...

01 Oct 2022

Unique Morse Code Words Problem

LeetCode 804. International Morse Code defines a standard encoding where...

01 Oct 2022

Unique Email Addresses Problem

LeetCode 929. Every valid email consists of a local name...

01 Oct 2022

Uncommon Words From Two Sentences Problem

LeetCode 884. A sentence is a string of single-space separated...

01 Oct 2022

Triples With Bitwise And Equal To Zero Problem

LeetCode 982. Given an integer array nums, return the number...

01 Oct 2022

Time Based Key-Value Store Problem

LeetCode 981. Design a time-based key-value data structure that can...

01 Oct 2022

Subdomain Visit Count Problem

LeetCode 811. A website domain “discuss.leetcode.com” consists of various subdomains....

01 Oct 2022

Subarrays With K Different Integers Problem

LeetCode 992. Given an integer array nums and an integer...

01 Oct 2022

Smallest Subtree With All The Deepest Nodes Problem

LeetCode 865. Given the root of a binary tree, the...

01 Oct 2022

Short Encoding Of Words Problem

LeetCode 820. A valid encoding of an array of words...

01 Oct 2022

Prison Cells After N Days Problem

LeetCode 957. There are 8 prison cells in a row...

01 Oct 2022

Powerful Integers Problem

LeetCode 970. Given three integers x, y, and bound, return...

01 Oct 2022

Online Election Problem

LeetCode 911. You are given two integer arrays persons and...

01 Oct 2022

Most Common Word Problem

LeetCode 819. Given a string paragraph and a string array...

01 Oct 2022

Minimum Area Rectangle Problem

LeetCode 939. You are given an array of points in...

01 Oct 2022

Maximum Frequency Stack Problem

LeetCode 895. Design a stack-like data structure to push elements...

01 Oct 2022

Linked List Components Problem

LeetCode 817. You are given the head of a linked...

01 Oct 2022

Length Of Longest Fibonacci Subsequence Problem

LeetCode 873. Given a strictly increasing array arr of positive...

01 Oct 2022

Hand Of Straights Problem

LeetCode 846. Alice has some number of cards and she...

01 Oct 2022

Groups Of Special-Equivalent Strings Problem

LeetCode 893. You are given an array of strings of...

01 Oct 2022

Fruit Into Baskets Problem

LeetCode 904. You are visiting a farm that has a...

01 Oct 2022

Find The Town Judge Problem

LeetCode 997. In a town, there are n people labeled...

01 Oct 2022

Find And Replace Pattern Problem

LeetCode 890. Given a list of strings words and a...

01 Oct 2022

Fair Candy Swap Problem

LeetCode 888. Alice and Bob have a different total number...

01 Oct 2022

Count Unique Characters Of All Substrings Of A Given String Problem

LeetCode 828. Let’s define a function countUniqueChars(s) that returns the...

01 Oct 2022

Construct Binary Tree From Preorder And Postorder Traversal Problem

LeetCode 889. Given two integer arrays, preorder and postorder where...

30 Sep 2022

Card Flipping Game Problem

LeetCode 822. You are given n cards, with a positive...

30 Sep 2022

Bus Routes Problem

LeetCode 815. You are given an array routes representing bus...

30 Sep 2022

Buddy Strings Problem

LeetCode 859. Given two strings s and goal, return true...

30 Sep 2022

Binary Trees With Factors Problem

LeetCode 823. Given an array of unique integers, arr, where...

30 Sep 2022

Binary Subarrays With Sum Problem

LeetCode 930. Given a binary array nums and an integer...

30 Sep 2022

Array Of Doubled Pairs Problem

LeetCode 954. Given an integer array of even length arr,...

30 Sep 2022

3Sum With Multiplicity Problem

LeetCode 923. Given an integer array arr, and an integer...

30 Sep 2022

Top K Frequent Words Problem

LeetCode 692. Given an array of strings words and an...

28 Sep 2022

Task Scheduler Problem

LeetCode 621. Given a characters array tasks, representing the tasks...

28 Sep 2022

Set Mismatch Problem

LeetCode 645. You have a set of integers s, which...

28 Sep 2022

Reorganize String Problem

LeetCode 767. Given a string s, rearrange the characters of...

28 Sep 2022

Random Pick With Blacklist Problem

LeetCode 710. You are given an integer n and an...

28 Sep 2022

Rabbits In Forest Problem

LeetCode 781. There is a forest with an unknown number...

28 Sep 2022

Partition Labels Problem

LeetCode 763. You are given a string s. We want...

28 Sep 2022

Parse Lisp Expression Problem

LeetCode 736. You are given a string expression representing a...

28 Sep 2022

Open The Lock Problem

LeetCode 752. You have a lock in front of you...

28 Sep 2022

Two Sum IV - Input Is A BST Problem

LeetCode 653. Given the root of a Binary Search Tree...

27 Sep 2022

Split Array Into Consecutive Subsequences Problem

LeetCode 659. You are given an integer array nums that...

27 Sep 2022

Smallest Range Covering Elements From K Lists Problem

LeetCode 632. You have k lists of sorted integers in...

27 Sep 2022

Shortest Completing Word Problem

LeetCode 748. Given a string licensePlate and an array of...

27 Sep 2022

Prefix And Suffix Search Problem

LeetCode 745. Design a special dictionary with some words that...

27 Sep 2022

Number Of Matching Subsequences Problem

LeetCode 792. Given a string s and an array of...

27 Sep 2022

Number Of Atoms Problem

LeetCode 726. Given a string formula representing a chemical formula,return...

27 Sep 2022

Find Duplicate File In System Problem

LeetCode 609. Given a list paths of directory info, including...

27 Sep 2022

Map Sum Pairs Problem

LeetCode 677. Design a map that allows you to do...

26 Sep 2022

Implement Magic Dictionary Problem

LeetCode 676. Design a data structure that is initialized with...

26 Sep 2022

Find Duplicate Subtrees Problem

LeetCode 652. Given the rootof a binary tree, return all...

26 Sep 2022

Employee Importance Problem

LeetCode 690. You have a data structure of employee information,...

26 Sep 2022

Design Hashset Problem

LeetCode 705. Design a HashSet without using any built-in hash...

26 Sep 2022

Design Hashmap Problem

LeetCode 706. Design a HashMap without using any built-in hash...

26 Sep 2022

Delete And Earn Problem

LeetCode 740. You are given an integer array nums. You...

26 Sep 2022

Degree Of An Array Problem

LeetCode 697. Given a non-empty array of non-negative integers nums,...

26 Sep 2022

Custom Sort String Problem

LeetCode 791. You are given two strings order and s....

26 Sep 2022

Basic Calculator IV Problem

LeetCode 770. Given an expression such as expression = “e...

26 Sep 2022

Sort Characters By Frequency Problem

LeetCode 451. Given a string s, sort it in decreasing...

24 Sep 2022

Sliding Window Median Problem

LeetCode 480. The median is the middle value in an...

24 Sep 2022

Reconstruct Original Digits From English Problem

LeetCode 423. Given a string s containing an out-of-order English...

24 Sep 2022

Random Flip Matrix Problem

LeetCode 519. There is an m x n binary grid...

24 Sep 2022

Permutation In String Problem

LeetCode 567. Given two strings s1 and s2, return true...

24 Sep 2022

Number Of Boomerangs Problem

LeetCode 447. You are given n points in the plane...

23 Sep 2022

Next Greater Element I Problem

LeetCode 496. The next greater element of some element x...

23 Sep 2022

Most Frequent Subtree Sum Problem

LeetCode 508. Given the root of a binary tree, return...

23 Sep 2022

Minimum Genetic Mutation Problem

LeetCode 433. A gene string can be represented by an...

23 Sep 2022

Minimum Index Sum Of Two Lists Problem

LeetCode 599. Suppose Andy and Doris want to choose a...

22 Sep 2022

Longest Uncommon Subsequence II Problem

LeetCode 522. Given an array of strings strs, return the...

22 Sep 2022

Longest Repeating Character Replacement Problem

LeetCode 424. You are given a string s and an...

22 Sep 2022

Longest Palindrome Problem

LeetCode 409. Given a string s which consists of lowercase...

22 Sep 2022

Longest Harmonious Subsequence Problem

LeetCode 594. We define a harmonious array as an array...

22 Sep 2022

LFU Cache Problem

LeetCode 460. Design and implement a data structure for a...

22 Sep 2022

Keyboard Row Problem

LeetCode 500. Given an array of strings words, return the...

22 Sep 2022

K-Diff Pairs In An Array Problem

LeetCode 532. Given an array of integers nums and an...

22 Sep 2022

Increasing Subsequences Problem

LeetCode 491. Given an integer array nums, return all the...

22 Sep 2022

Find Right Interval Problem

LeetCode 436. You are given an array of intervals, where...

21 Sep 2022

Find All Numbers Disappeared In An Array Problem

LeetCode 448. Given an array nums of n integers where...

21 Sep 2022

Find All Duplicates In An Array Problem

LeetCode 442. Given an integer array nums of length n...

21 Sep 2022

Find All Anagrams In A String Problem

LeetCode 438. Given two strings s and p, return an...

21 Sep 2022

Encode And Decode TinyURL Problem

LeetCode 535. TinyURL is a URL shortening service where you...

21 Sep 2022

Distribute Candies Problem

LeetCode 575. Alice has n candies, where the i^th candy...

21 Sep 2022

Contiguous Array Problem

LeetCode 525. Given a binary array nums, return the maximum...

21 Sep 2022

Circular Array Loop Problem

LeetCode 457. You are playing a game involving a circular...

19 Sep 2022

Brick Wall Problem

LeetCode 554. There is a rectangular brick wall in front...

19 Sep 2022

All O'One Data Structure Problem

LeetCode 432. Design a data structure to store the strings...

19 Sep 2022

Valid Anagram Problem

LeetCode 242. Given two strings s and t, return true...

18 Sep 2022

Ugly Number II Problem

LeetCode 264. An ugly number is a positive integer whose...

18 Sep 2022

Top K Frequent Elements Problem

LeetCode 347. Given an integer array nums and an integer...

18 Sep 2022

Word Pattern Problem

LeetCode 290. Given a pattern and a string s, find...

16 Sep 2022

Ransom Note Problem

LeetCode 383. Given two stings ransomNote and magazine, return true...

16 Sep 2022

Random Pick Index Problem

LeetCode 398. Given an integer array nums with possible duplicates,...

16 Sep 2022

Palindrome Pairs Problem

LeetCode 336. Given a list of unique words, return all...

16 Sep 2022

Missing Number Problem

LeetCode 268. Given an array nums containing n distinct numbers...

15 Sep 2022

Majority Element II Problem

LeetCode 229. Given an integer array of size n, find...

10 Apr 2022

Longest Substring With At Least K Repeating Characters Problem

LeetCode 395. Given a string s and an integer k,...

10 Apr 2022

Isomorphic Strings Problem

LeetCode 205. Given two strings s and t, determine if...

10 Apr 2022

Intersection Of Two Arrays II Problem

LeetCode 350. Given two integer arrays nums1 and nums2, return...

10 Apr 2022

Insert Delete Getrandom O(1) - Duplicates Allowed Problem

LeetCode 381. RandomizedCollection is a data structure that contains a...

10 Apr 2022

Happy Number Problem

LeetCode 202. Write an algorithm to determine if a number...

10 Apr 2022

First Unique Character In A String Problem

LeetCode 387. Given a string s, find the first non-repeating...

10 Apr 2022

Find The Difference Problem

LeetCode 389. You are given two strings s and t....

10 Apr 2022

Design Twitter Problem

LeetCode 355. Design a simplified version of Twitter where users...

10 Apr 2022

Contains Duplicate Problem

LeetCode 217. Given an integer array nums, return true if...

10 Apr 2022

Contains Duplicate II Problem

LeetCode 219. Given an integer array nums and an integer...

10 Apr 2022

Bulls And Cows Problem

LeetCode 299. You are playing the Bulls and Cows game...

10 Apr 2022

Repeated DNA Sequences Problem

LeetCode 187. The DNA sequence is composed of a series...

04 Dec 2021

Majority Element Problem

LeetCode 169. Given an array nums of size n, return...

04 Dec 2021

Intersection Of Two Linked Lists Problem

LeetCode 160. Given the heads of two singly linked-lists headA...

04 Dec 2021

Fraction To Recurring Decimal Problem

LeetCode 166. Given two integers representing the numerator and denominator...

04 Dec 2021

Word Break Problem

LeetCode 139. Given a string s and a dictionary of...

03 Dec 2021

Word Break II Problem

LeetCode 140. Given a string s and a dictionary of...

03 Dec 2021

Max Points On A Line Problem

LeetCode 149. Given an array of points where points[i] =...

03 Dec 2021

Lru Cache Problem

LeetCode 146. Design a data structure that follows the constraints...

03 Dec 2021

Linked List Cycle Problem

LeetCode 141. Given head, the head of a linked list,...

03 Dec 2021

Linked List Cycle II Problem

LeetCode 142. Given the head of a linked list, return...

03 Dec 2021

Copy List With Random Pointer Problem

LeetCode 138. A linked list of length n is given...

03 Dec 2021

Clone Graph Problem

LeetCode 133. Given a reference of a node in a...

03 Dec 2021

Word Ladder Problem

LeetCode 127. Given two words, beginWord and endWord, and a...

29 Nov 2021

Word Ladder II Problem

LeetCode 126. Given two words, beginWord and endWord, and a...

29 Nov 2021

Longest Consecutive Sequence Problem

LeetCode 128. Given an unsorted array of integers nums, return...

29 Nov 2021

Construct Binary Tree from Preorder and Inorder Traversal Problem

LeetCode 105. Given two integer arrays preorder and inorder where...

20 Nov 2021

Set Matrix Zeroes Problem

LeetCode 73. Given an m x n integer matrix matrix,...

10 Nov 2021

Search in Rotated Sorted Array Problem

LeetCode 36. Determine if a 9 x 9 Sudoku board...

06 Nov 2021

Substring with Concatenation of All Words Problem

LeetCode 30. You are given a string s and an...

06 Nov 2021

Integer to Roman Problem

LeetCode 12. Given an integer, convert it to a roman...

06 Nov 2021

Group Anagrams Problem

LeetCode 49. Given an array of strings strs, group the...

06 Nov 2021

First Missing Positive Problem

LeetCode 41. Given an unsorted integer array nums, return the...

06 Nov 2021

Roman to Integer Problem

LeetCode 13. Given a roman numeral, convert it to an...

05 Nov 2021

Letter Combinations of a Phone Number Problem

LeetCode 17. Given a string containing digits from 2-9 inclusive,...

05 Nov 2021

Longest Substring Without Repeating Characters Problem

LeetCode 3. Given a string s, find the length of...

05 Mar 2021

Sum Of Unique Elements Problem

LeetCode 1748. You are given an integer array nums. The...

15 Feb 2021

Insert Delete GetRandom O(1) Problem

LeetCode 380. Implement a RandomizedSet class.

03 Feb 2021

N-Repeated Element In Size 2N Array Problem

LeetCode 961. In a array A of size 2N, there...

31 Jan 2021

Intersection Of Two Arrays Problem

LeetCode 349. Given two arrays, write a function to compute...

31 Jan 2021

Intersection Of Three Sorted Arrays Problem

LeetCode 1213. Given three integer arrays arr1, arr2 and arr3...

31 Jan 2021

Jewels And Stones Problem

LeetCode 771. You’re given strings jewels representing the types of...

27 Jan 2021

Number Of Good Pairs Problem

LeetCode 1512. Given an array of integers nums. Return the...

26 Jan 2021

Kth Missing Positive Number Problem

LeetCode 1539. Given an array arr of positive integers sorted...

25 Jan 2021

Maximum Equal Frequency Problem

LeetCode 1224. Given an array nums of positive integers, return...

08 Dec 2020

Subarray Sum Divisible By K Problem

LeetCode 974. Given an array of integers nums and an...

12 Nov 2020

Four Sum II Problem

LeetCode 454. Given four lists A, B, C, D of...

12 Nov 2020

Continuous Subarray Sum Problem

LeetCode 523. Given an array of non-negative integers nums and...

12 Nov 2020

Subarray Sum Equals K Problem

LeetCode 560. Given an array of integers nums and an...

11 Nov 2020

Two Sum Problem

LeetCode 1. Given an array of integers nums and an...

09 Nov 2020

Tag Leetcode

Symmetric Tree Problem

LeetCode 101. Given the root of a binary tree, check...

20 Nov 2021

Maximum Depth of Binary Tree Problem

LeetCode 104. Given the root of a binary tree, return...

20 Nov 2021

Construct Binary Tree from Preorder and Inorder Traversal Problem

LeetCode 105. Given two integer arrays preorder and inorder where...

20 Nov 2021

Construct Binary Tree From Inorder And Postorder Traversal Problem

LeetCode 106. Given two integer arrays inorder and postorder where...

20 Nov 2021

Binary Tree Zigzag Level Order Traversal Problem

LeetCode 103. Given the root of a binary tree, return...

20 Nov 2021

Binary Tree Level Order Traversal Problem

LeetCode 102. Given the root of a binary tree, return...

20 Nov 2021

Binary Tree Level Order Traversal II Problem

LeetCode 107. Given the root of a binary tree, return...

20 Nov 2021

Validate Binary Search Tree Problem

LeetCode 98. Given the root of a binary tree, determine...

16 Nov 2021

Same Tree Problem

LeetCode 100. Given the roots of two binary trees p...

16 Nov 2021

Recover Binary Search Tree Problem

LeetCode 99. You are given the root of a binary...

16 Nov 2021

Interleaving String Problem

LeetCode 97. Given strings s1, s2, and s3, find whether...

16 Nov 2021

Word Search Problem

LeetCode 79. Given an m x n grid of characters...

14 Nov 2021

Unique Binary Search Trees Problem

LeetCode 96. Given an integer n, return the number of...

14 Nov 2021

Unique Binary Search Trees II Problem

LeetCode 95. Given an integer n, return all the structurally...

14 Nov 2021

Subsets Problem

LeetCode 78. Given an integer array nums of unique elements,...

14 Nov 2021

Subsets II Problem

LeetCode 90. Given an integer array nums that may contain...

14 Nov 2021

Search in Rotated Sorted Array II Problem

LeetCode 81. There is an integer array nums sorted in...

14 Nov 2021

Scramble String Problem

LeetCode 87. Given two strings s1 and s2 of the...

14 Nov 2021

Restore IP Addresses Problem

LeetCode 93. Given a string s containing only digits, return...

14 Nov 2021

Remove Duplicates from Sorted List Problem

LeetCode 83. Given the head of a sorted linked list,...

14 Nov 2021

Remove Duplicates from Sorted List II Problem

LeetCode 82. Given the head of a sorted linked list,...

14 Nov 2021

Remove Duplicates from Sorted Array II Problem

LeetCode 80. Given an integer array nums sorted in non-decreasing...

14 Nov 2021

Partition List Problem

LeetCode 86. Given the head of a linked list and...

14 Nov 2021

Merge Sorted Array Problem

LeetCode 88. You are given two integer arrays nums1 and...

14 Nov 2021

Maximal Rectangle Problem

LeetCode 85. Given a rows x cols binary matrix filled...

14 Nov 2021

Largest Rectangle in Histogram Problem

LeetCode 84. Given an array of integers heights representing the...

14 Nov 2021

Gray Code Problem

LeetCode 89. Given an integer n, return any valid n-bit...

14 Nov 2021

Decode Ways Problem

LeetCode 91. Given a string s containing only digits, return...

14 Nov 2021

Binary Tree Inorder Traversal Problem

LeetCode 94. Given an m x n grid of characters...

14 Nov 2021

Sort Colors Problem

LeetCode 75. Given an array nums with n objects colored...

10 Nov 2021

Simplify Path Problem

LeetCode 71. Given a string path, which is an absolute...

10 Nov 2021

Set Matrix Zeroes Problem

LeetCode 73. Given an m x n integer matrix matrix,...

10 Nov 2021

Search A 2D Matrix Problem

LeetCode 74. Write an efficient algorithm that searches for a...

10 Nov 2021

Minimum Window Substring Problem

LeetCode 76. Given two strings s and t of lengths...

10 Nov 2021

Edit Distance Problem

LeetCode 72. Given two strings word1 and word2, return the...

10 Nov 2021

Combinations Problem

LeetCode 77. Given two integers n and k, return all...

10 Nov 2021

Valid Number Problem

LeetCode 65. Given a string s, return true if s...

09 Nov 2021

Unique Paths Problem

LeetCode 62. A robot is located at the top-left corner...

09 Nov 2021

Unique Paths II Problem

LeetCode 63. A robot is located at the top-left corner...

09 Nov 2021

Text Justification Problem

LeetCode 68. Given an array of strings words and a...

09 Nov 2021

Rotate List Problem

LeetCode 61. Given the head of a linked list, rotate...

09 Nov 2021

Plus One Problem

LeetCode 66. You are given a large integer represented as...

09 Nov 2021

Minimum Path Sum Problem

LeetCode 64. Given a m x n grid filled with...

09 Nov 2021

Climbing Stairs Problem

LeetCode 70. You are climbing a staircase. It takes n...

09 Nov 2021

Valid Number Problem

LeetCode 67. A robot is located at the top-left corner...

09 Nov 2021

Spiral Matrix Problem

LeetCode 54. Given an m x n matrix, return all...

08 Nov 2021

Spiral Matrix II Problem

LeetCode 59. Given a positive integer n, generate an n...

08 Nov 2021

Permutation Sequence Problem

LeetCode 60. Given n and k, return the kth permutation...

08 Nov 2021

N-Queens Problem

LeetCode 51. Given an integer n, return all distinct solutions...

08 Nov 2021

N-Queens II Problem

LeetCode 52. Given an integer n, return the number of...

08 Nov 2021

Maximum Subarray Problem

LeetCode 53. Given an integer array nums, find the contiguous...

08 Nov 2021

Length Of Last Word Problem

LeetCode 58. Given a string s consisting of some words...

08 Nov 2021

Jump Game Problem

LeetCode 55. Given an m x n matrix, return all...

08 Nov 2021

Insert Interval Problem

LeetCode 57. Insert newInterval into intervals such that intervals is...

08 Nov 2021

Zigzag Conversion Problem

LeetCode 6. Write the code that will take a string...

06 Nov 2021

Wildcard Matching Problem

LeetCode 44. Write the code that will take a string...

06 Nov 2021

Search in Rotated Sorted Array Problem

LeetCode 36. Determine if a 9 x 9 Sudoku board...

06 Nov 2021

Trapping Rain Water Problem

LeetCode 42. Given n non-negative integers representing an elevation map...

06 Nov 2021

Sudoku Solver Problem

LeetCode 37. Write a program to solve a Sudoku puzzle...

06 Nov 2021

Substring with Concatenation of All Words Problem

LeetCode 30. You are given a string s and an...

06 Nov 2021

Search in Rotated Sorted Array Problem

LeetCode 33. Given the array nums after the possible rotation...

06 Nov 2021

Rotate Image Problem

LeetCode 48. Determine if a 9 x 9 Sudoku board...

06 Nov 2021

Reverse Nodes in k-Group Problem

LeetCode 25. Given a linked list, reverse the nodes of...

06 Nov 2021

Remove Element Problem

LeetCode 27. Given an integer array nums and an integer...

06 Nov 2021

Regular Expression Matching Problem

LeetCode 10. Given an input string s and a pattern...

06 Nov 2021

Pow(x,n) Problem

LeetCode 50. Determine if a 9 x 9 Sudoku board...

06 Nov 2021

Permutations Problem

LeetCode 46. Given an array nums of distinct integers, return...

06 Nov 2021

Permutations II Problem

LeetCode 47. Given a collection of numbers, nums, that might...

06 Nov 2021

Palindrome Number Problem

LeetCode 9. Given an integer x, return true if x...

06 Nov 2021

Next Permutation Problem

LeetCode 31. Implement next permutation, which rearranges numbers into the...

06 Nov 2021

Multiply Strings Problem

LeetCode 43. Given two non-negative integers num1 and num2 represented...

06 Nov 2021

Jump Game II Problem

LeetCode 45. Given an array of non-negative integers nums, you...

06 Nov 2021

Integer to Roman Problem

LeetCode 12. Given an integer, convert it to a roman...

06 Nov 2021

Implement strStr() Problem

LeetCode 28. Implement strStr().

06 Nov 2021

Group Anagrams Problem

LeetCode 49. Given an array of strings strs, group the...

06 Nov 2021

First Missing Positive Problem

LeetCode 41. Given an unsorted integer array nums, return the...

06 Nov 2021

Find First and Last Position of Element in Sorted Array Problem

LeetCode 34. Given the array nums after the possible rotation...

06 Nov 2021

Divide Two Integers Problem

LeetCode 29. Write the code that will take a string...

06 Nov 2021

Count and Say Problem

LeetCode 38. Write the code that will take a string...

06 Nov 2021

Combination Sum Problem

LeetCode 39. Given an array of distinct integers candidates and...

06 Nov 2021

Combination Sum II Problem

LeetCode 40. Given a collection of candidate numbers (candidates) and...

06 Nov 2021

3Sum Closest Problem

LeetCode 16. Given an integer array nums of length n...

06 Nov 2021

Valid Parentheses Problem

LeetCode 20. Given a string s containing just the characters...

05 Nov 2021

Swap Nodes in Pairs Problem

LeetCode 24. Given a linked list, swap every two adjacent...

05 Nov 2021

Roman to Integer Problem

LeetCode 13. Given a roman numeral, convert it to an...

05 Nov 2021

Reverse Integer Problem

LeetCode 7. Given a signed 32-bit integer x, return x...

05 Nov 2021

Remove Nth Node From End of List Problem

LeetCode 19. Given the head of a linked list, remove...

05 Nov 2021

Remove Duplicates from Sorted Array Problem

LeetCode 26. Given an integer array nums sorted in non-decreasing...

05 Nov 2021

Longest Palindromic Substring Problem

LeetCode 5. Given a string s, return the longest palindromic...

05 Nov 2021

Longest Common Prefix Problem

LeetCode 14. Write a function to find the longest common...

05 Nov 2021

Letter Combinations of a Phone Number Problem

LeetCode 17. Given a string containing digits from 2-9 inclusive,...

05 Nov 2021

Generate Parentheses Problem

LeetCode 22. Given n pairs of parentheses, write a function...

05 Nov 2021

Depth of BST Given Insertion Order Problem

LeetCode 1902. You are given a 0-indexed integer array order...

05 Nov 2021

Container With Most Water Problem

LeetCode 11. Given n non-negative integers a_1, a_2, …, a_n...

05 Nov 2021

Smallest Greater Multiple Made of Two Digits Problem

LeetCode 1999. Given three integers, k, digit1, and digit2, you...

12 Sep 2021

Reverse Prefix of Word Problem

LeetCode 2000. Given a 0-indexed string word and a character...

12 Sep 2021

Users That Actively Request Confirmation Messages Problem

LeetCode 1939. Write an SQL query to find the IDs...

11 Sep 2021

Strong Friendship Problem

LeetCode 1949. Write an SQL query to find all the...

11 Sep 2021

Leetcodify Similar Friends Problem

LeetCode 1919. Write an SQL query to report the similar...

11 Sep 2021

Leetcodify Friends Recommendations Problem

LeetCode 1917. Write an SQL query to recommend friends to...

11 Sep 2021

First and Last Call On the Same Day Problem

LeetCode 1972. Write an SQL query to report the IDs...

11 Sep 2021

Find Cutoff Score for Each School Problem

LeetCode 1988. Write an SQL query to report the minimum...

11 Sep 2021

Employees With Missing Information Problem

LeetCode 1965. Write an SQL query to report the IDs...

11 Sep 2021

Employees Whose Manager Left the Company Problem

LeetCode 1978. Write an SQL query to report the IDs...

11 Sep 2021

Count the Number of Experiments Problem

LeetCode 1990. Write an SQL query to report the number...

11 Sep 2021

Count Salary Categories Problem

LeetCode 1907. Write an SQL query to report the number...

11 Sep 2021

Confirmation Rate Problem

LeetCode 1934. Write an SQL query to find the confirmation...

11 Sep 2021

All the Pairs With the Maximum Number of Common Followers Problem

LeetCode 1951. Write an SQL query to find all the...

11 Sep 2021

The Latest Login in 2020 Problem

LeetCode 1890. Write an SQL query to report the latest...

13 Jun 2021

Suspicious Bank Accounts Problem

LeetCode 1843. Write an SQL query to report the IDs...

13 Jun 2021

Page Recommendations II Problem

LeetCode 1892. Write an SQL query to find all the...

13 Jun 2021

Orders With Maximum Quantity Above Average Problem

LeetCode 1867. Write an SQL query to find the order_id...

13 Jun 2021

Maximum Transaction Each Day Problem

LeetCode 1831. Write an SQL query to report the IDs...

13 Jun 2021

League Statistics Problem

LeetCode 1841. Write an SQL query to report the statistics...

13 Jun 2021

Group Employees of the Same Salary Problem

LeetCode 1875. Write an SQL query to report the IDs...

13 Jun 2021

Find Customers With Positive Revenue this Year Problem

LeetCode 1821. Write an SQL query to report the customers...

13 Jun 2021

Convert Date Format Problem

LeetCode 1853. Write an SQL query to convert each date...

13 Jun 2021

Calculate Special Bonus Problem

LeetCode 1873. Write an SQL query to calculate the bonus...

13 Jun 2021

Rearrange Products Table Problem

LeetCode 1795. Write an SQL query to rearrange the Products...

03 Apr 2021

Find Interview Candidates Problem

LeetCode 1811. Write an SQL query to report the name...

03 Apr 2021

Determine Color Of A Chessboard Square Problem

LeetCode 1812. You are given coordinates, a string that represents...

03 Apr 2021

Ad-Free Sessions Problem

LeetCode 1809. Write an SQL query to report all the...

03 Apr 2021

String To Interger (atoi) Problem

LeetCode 8. Implement the myAtoi(string s) function, which converts a...

17 Mar 2021

Primary Department For Each Employee Problem

LeetCode 1789. Write an SQL query to report all the...

17 Mar 2021

Grand Slam Titles Problem

LeetCode 1783. Write an SQL query to report the number...

08 Mar 2021

Product's Price For Each Store Problem

LeetCode 1777. Write an SQL query to find the price...

05 Mar 2021

Longest Substring Without Repeating Characters Problem

LeetCode 3. Given a string s, find the length of...

05 Mar 2021

Find The Subtasks That Did Not Execute Problem

LeetCode 1767. Write an SQL query to report the IDs...

05 Mar 2021

Add Two Numbers Problem

LeetCode 2. You are given two non-empty linked lists representing...

05 Mar 2021

Sum Of Unique Elements Problem

LeetCode 1748. You are given an integer array nums. The...

15 Feb 2021

Recyclable And Low Fat Products Problem

LeetCode 1757. Write an SQL query to find the ids...

14 Feb 2021

Leetflex Banned Accounts Problem

LeetCode 1747. Write an SQL query to find the account_id...

10 Feb 2021

Insert Delete GetRandom O(1) Problem

LeetCode 380. Implement a RandomizedSet class.

03 Feb 2021

N-Repeated Element In Size 2N Array Problem

LeetCode 961. In a array A of size 2N, there...

31 Jan 2021

Intersection Of Two Arrays Problem

LeetCode 349. Given two arrays, write a function to compute...

31 Jan 2021

Intersection Of Three Sorted Arrays Problem

LeetCode 1213. Given three integer arrays arr1, arr2 and arr3...

31 Jan 2021

Find Total Time Spent By Each Employee Problem

LeetCode 1741. Write an SQL query to calculate the total...

31 Jan 2021

Jewels And Stones Problem

LeetCode 771. You’re given strings jewels representing the types of...

27 Jan 2021

Number Of Good Pairs Problem

LeetCode 1512. Given an array of integers nums. Return the...

26 Jan 2021

Kth Missing Positive Number Problem

LeetCode 1539. Given an array arr of positive integers sorted...

25 Jan 2021

The Number Of Employees Which Report To Each Employee Problem

LeetCode 1731. Write an SQL query to report the ids...

24 Jan 2021

Find Followers Count Problem

LeetCode 1729. Write an SQL query that will, for each...

20 Jan 2021

Count Apples And Oranges Problem

LeetCode 1715. Write an SQL query to count the number...

09 Jan 2021

Biggest Window Between Visits Problem

LeetCode 1709. Write an SQL query that will, for each...

04 Jan 2021

Total Sales Amount By Year Problem

LeetCode 1384. Write an SQL query to report the Total...

29 Dec 2020

Sales By Day Of The Week Problem

LeetCode 1479. Write an SQL query to report how many...

29 Dec 2020

Hopper Company Queries III Problem

LeetCode 1651. Write an SQL query to compute the average_ride_distance...

29 Dec 2020

Get The Second Most Recent Activity Problem

LeetCode 1369. Write an SQL query to show the second...

29 Dec 2020

Find The Quiet Students In All Exams Problem

LeetCode 1412. Write an SQL query to report the students...

29 Dec 2020

Tournament Winners Problem

LeetCode 1194. Write an SQL query to find the winner...

28 Dec 2020

Students Report By Geography Problem

LeetCode 618. A U.S graduate school has students from Asia,...

28 Dec 2020

Report Contiguous Dates Problem

LeetCode 1225. Write an SQL query to generate a report...

28 Dec 2020

Median Employee Salary Problem

LeetCode 569. Write a SQL query to find the median...

28 Dec 2020

Market Analysis II Problem

LeetCode 1159. Write an SQL query to find for each...

28 Dec 2020

Hopper Company Queries I Problem

LeetCode 1635. Write an SQL query to report the following...

28 Dec 2020

Game Play Analysis V Problem

LeetCode 1097. Write an SQL query that reports for each...

28 Dec 2020

User Purchase Platform Problem

LeetCode 1127. Write an SQL query to find the total...

27 Dec 2020

Trips And Users Problem

LeetCode 262. Write a SQL query to find the cancellation...

27 Dec 2020

Number Of Transactions Per Visit Problem

LeetCode 1336. Write an SQL query to find how many...

27 Dec 2020

Human Traffic Of Stadium Problem

LeetCode 601. Write an SQL query to display the records...

27 Dec 2020

Hopper Company Queries II Problem

LeetCode 1645. Write an SQL query to report the percentage...

27 Dec 2020

Find Median Given Frequency Of Numbers Problem

LeetCode 571. Write a query to find the median of...

27 Dec 2020

Find Cumulative Salary Of An Employee Problem

LeetCode 579. Write a SQL to get the cumulative sum...

27 Dec 2020

Department Top Three Salaries Problem

LeetCode 185. Write a SQL query to find employees who...

27 Dec 2020

Average Salary: Departments VS Company Problem

LeetCode 615. Given two tables as below, write a query...

27 Dec 2020

Unpopular Books Problem

LeetCode 1098. Write an SQL query that reports the books...

26 Dec 2020

Second Degree Follower Problem

LeetCode 614. Please write a sql query to get the...

26 Dec 2020

Reported Posts II Problem

LeetCode 1132. Write an SQL query to find the average...

26 Dec 2020

Number Of Calls Between Two Persons Problem

LeetCode 1699. Write an SQL query to report the number...

26 Dec 2020

Nth Highest Salary Problem

LeetCode 177. Write a SQL query to get the nth...

26 Dec 2020

New Users Daily Count Problem

LeetCode 1107. Write an SQL query that reports for every...

26 Dec 2020

Monthly Transactions II Problem

LeetCode 1205. Write an SQL query to find for each...

26 Dec 2020

Get Highest Answer Rate Question Problem

LeetCode 578. Write a sql query to identify the question...

26 Dec 2020

Department Highest Salary Problem

LeetCode 184. Write a SQL query to find employees who...

26 Dec 2020

Article Views II Problem

LeetCode 1149. Write an SQL query to find all the...

26 Dec 2020

Active Users Problem

LeetCode 1454. Write an SQL query to find the id...

26 Dec 2020

Winning Candidate Problem

LeetCode 574. Write a sql to find the name of...

25 Dec 2020

Team Scores In Football Tournament Problem

LeetCode 1212. Write an SQL query that selects the team_id,...

25 Dec 2020

Rank Scores Problem

LeetCode 178. Write a SQL query to rank scores. If...

25 Dec 2020

Product Sales Analysis III Problem

LeetCode 1070. Write an SQL query that selects the product...

25 Dec 2020

Movie Rating Problem

LeetCode 1341. Write the following SQL query to find the...

25 Dec 2020

Investments In 2016 Problem

LeetCode 585. Write a query to print the sum of...

25 Dec 2020

Immediate Food Delivery II Problem

LeetCode 1174. Write an SQL query to find the percentage...

25 Dec 2020

Friend Requests II: Who Has The Most Friends Problem

LeetCode 602. In social network like Facebook or Twitter, people...

25 Dec 2020

Countries You Can Safely Invest In Problem

LeetCode 1501. Write an SQL query to find the countries...

25 Dec 2020

Count Student Number In Departments Problem

LeetCode 580. A university uses 2 data tables, student and...

25 Dec 2020

Bank Account Summary Problem

LeetCode 1555. Our bank records all transactions in the table...

25 Dec 2020

Tree Node Problem

LeetCode 608. Given a table tree, id is identifier of...

23 Dec 2020

The Most Recent Orders For Each Product Problem

LeetCode 1549. Write an SQL query to find the most...

23 Dec 2020

Shortest Distance In A Plane Problem

LeetCode 612. Write a query to find the shortest distance...

23 Dec 2020

Rectangles Area Problem

LeetCode 1459. Write an SQL query to report of all...

23 Dec 2020

Product Price At A Given Date Problem

LeetCode 1164. Write an SQL query to find the prices...

23 Dec 2020

Page Recommendations Problem

LeetCode 1264. Write an SQL query to recommend pages to...

23 Dec 2020

Monthly Transactions I Problem

LeetCode 1193. Write an SQL query to find for each...

23 Dec 2020

Market Analysis I Problem

LeetCode 1158. Write an SQL query to find for each...

23 Dec 2020

Managers With At Least 5 Direct Reports Problem

LeetCode 570. Given the Employee table, write a SQL query...

23 Dec 2020

Find The Missing IDs Problem

LeetCode 1613. Write an SQL query to find the missing...

23 Dec 2020

Exchange Seats Problem

LeetCode 626. Mary is a teacher in a middle school...

23 Dec 2020

Customers Who Bought All Products Problem

LeetCode 1045. Write an SQL query for a report that...

23 Dec 2020

Active Business Problem

LeetCode 1126. Write an SQL query to find all active...

23 Dec 2020

The Most Recent Three Orders Problem

LeetCode 1532. Write an SQL query to find the most...

22 Dec 2020

Restaurant Growth Problem

LeetCode 1321. You are the restaurant owner and you want...

22 Dec 2020

Project Employees III Problem

LeetCode 1077. Write an SQL query that reports the most...

22 Dec 2020

Number Of Trusted Contacts Of A Customer Problem

LeetCode 1364. Write an SQL query to find the following...

22 Dec 2020

NPV Queries Problem

LeetCode 1421. Write an SQL query to find the npv...

22 Dec 2020

Last Person To Fit In The Elevator Problem

LeetCode 1204. Write an SQL query to find the person_name...

22 Dec 2020

Highest Grade For Each Student Problem

LeetCode 1112. Write a SQL query to find the highest...

22 Dec 2020

Evaluate Boolean Expression Problem

LeetCode 1440. Write an SQL query to evaluate the boolean...

22 Dec 2020

Calculate Salaries Problem

LeetCode 1468. Write an SQL query to find the salaries...

22 Dec 2020

Activity Participants Problem

LeetCode 1355. Write an SQL query to find the names...

22 Dec 2020

User Activity For The Past 30 Days II Problem

LeetCode 1142. Write an SQL query to find the average...

21 Dec 2020

The Most Frequently Ordered Products For Each Customer Problem

LeetCode 1596. Write an SQL query to find the most...

21 Dec 2020

Running Total For Different Genders Problem

LeetCode 1308. Write an SQL query to find the total...

21 Dec 2020

Friendly Movies Streamed Last Month Problem

LeetCode 1495. Write an SQL query to report the distinct...

21 Dec 2020

Friend Requests I: Overall Acceptance Rate Problem

LeetCode 597. Write an SQL query to find the overall...

21 Dec 2020

Find The Start And End Number Of Continuous Ranges Problem

LeetCode 1285. Write an SQL query to find the start...

21 Dec 2020

Customers Who Bought Products A And B But Not C Problem

LeetCode 1398. Write an SQL query to report the customer_id...

21 Dec 2020

Classes More Than 5 Students Problem

LeetCode 596. Please list out all classes which have more...

21 Dec 2020

Capital Gain/Loss Problem

LeetCode 1393. Write an SQL query to report the Capital...

21 Dec 2020

Biggest Single Number Problem

LeetCode 619. Table my_numbers contains many numbers in column num...

21 Dec 2020

Apples & Oranges Problem

LeetCode 1445. Write an SQL query to report the difference...

21 Dec 2020

All People Report To The Given Manager Problem

LeetCode 1270. Write an SQL query to find employee_id of...

21 Dec 2020

Weather Type In Each Country Problem

LeetCode 1294. Write an SQL query to find the type...

20 Dec 2020

User Activity For The Past 30 Days I Problem

LeetCode 1141. Write an SQL query to find the daily...

20 Dec 2020

Triangle Judgement Problem

LeetCode 610. A pupil Tim gets homework to identify whether...

20 Dec 2020

Students And Examinations Problem

LeetCode 1280. Write an SQL query to find the number...

20 Dec 2020

Sales Person Problem

LeetCode 607. Given three tables, salesperson, company, orders.

20 Dec 2020

Sales Analysis III Problem

LeetCode 1084. Write an SQL query that reports the products...

20 Dec 2020

Sales Analysis II Problem

LeetCode 1083. Write an SQL query that reports the buyers...

20 Dec 2020

Reported Posts Problem

LeetCode 1113. Write an SQL query that reports the number...

20 Dec 2020

Queries Quality And Percentage Problem

LeetCode 1211. Write an SQL query to find each query_name,...

20 Dec 2020

Project Employees II Problem

LeetCode 1076. Write an SQL query that reports all the...

20 Dec 2020

Project Employees I Problem

LeetCode 1075. Write an SQL query that reports the average...

20 Dec 2020

Number Of Comments Per Post Problem

LeetCode 1241. Write an SQL query to find number of...

20 Dec 2020

Not Boring Movies Problem

LeetCode 620. X city opened a new cinema, many people...

20 Dec 2020

Fix Product Name Format Problem

LeetCode 1543. Write an SQL query to report product_name in...

20 Dec 2020

Consecutive Available Seats Problem

LeetCode 603. Several friends at a cinema ticket office would...

20 Dec 2020

Ads Performance Problem

LeetCode 1322. A company is running Ads and wants to...

20 Dec 2020

Top Travellers Problem

LeetCode 1407. Write an SQL query to report the distance...

19 Dec 2020

Swap Salary Problem

LeetCode 627. Given a table salary, such as the one...

19 Dec 2020

Shortest Distance Problem

LeetCode 613. Write a query to find the shortest distance...

19 Dec 2020

Sales Analysis I Problem

LeetCode 1082. Write an SQL query that reports the best...

19 Dec 2020

Reformat Department Table Problem

LeetCode 1179. Write an SQL query to reformat the table...

19 Dec 2020

Product Sales Analysis II Problem

LeetCode 1069. Write an SQL query that reports the total...

19 Dec 2020

Product Sales Analysis I Problem

LeetCode 1068. Write an SQL query that reports all product...

19 Dec 2020

List The Products Ordered In A Period Problem

LeetCode 1327. Write an SQL query to get the names...

19 Dec 2020

Immediate Food Delivery I Problem

LeetCode 1173. Write an SQL query to find the percentage...

19 Dec 2020

Find Users With Valid Emails Problem

LeetCode 1517. Write an SQL query to find the users...

19 Dec 2020

Find Customer Referee Problem

LeetCode 584. Given a table customer holding customers information and...

19 Dec 2020

Customer Placing The Largest Number Of Orders Problem

LeetCode 586. Query the customer_number from the orders table for...

19 Dec 2020

Customer Order Frequency Problem

LeetCode 1511. Write an SQL query to report the customer_id...

19 Dec 2020

Create A Session Bar Chart Problem

LeetCode 1435. You want to know how long a user...

19 Dec 2020

Big Countries Problem

LeetCode 595. Write a SQL solution to output big countries’...

19 Dec 2020

Average Selling Price Problem

LeetCode 1251. Write an SQL query to find the average...

19 Dec 2020

Article Views I Problem

LeetCode 1148. Write an SQL query to find all the...

19 Dec 2020

Actors And Directors Who Cooperated At Least Three Times Problem

LeetCode 1050. Write a SQL query for a report that...

19 Dec 2020

Unique Orders And Customers Per Month Problem

LeetCode 1565. Write an SQL query to find the number...

18 Dec 2020

Sellers With No Sales Problem

LeetCode 1607. Write an SQL query to report the names...

18 Dec 2020

Rising Temperature Problem

LeetCode 197. Write an SQL query to find all dates’...

18 Dec 2020

Game Play Analysis IV Problem

LeetCode 550. Write an SQL query that reports the fraction...

18 Dec 2020

Game Play Analysis III Problem

LeetCode 534. Write an SQL query that reports for each...

18 Dec 2020

Game Play Analysis II Problem

LeetCode 512. Write a SQL query that reports the device...

18 Dec 2020

Game Play Analysis I Problem

LeetCode 511. Write an SQL query that reports the first...

18 Dec 2020

Employee Bonus Problem

LeetCode 577. Select all employee’s name and bonus whose bonus...

18 Dec 2020

Delete Duplicate Emails Problem

LeetCode 196. Write a SQL query to delete all duplicate...

18 Dec 2020

Daily Leads And Partners Problem

LeetCode 1693. Write an SQL query that will, for each...

18 Dec 2020

Customer Who Visited But Did Not Make Any Transactions Problem

LeetCode 1581. Write an SQL query to find the IDs...

18 Dec 2020

Product's Worth Over Invoices Problem

LeetCode 1677. Write an SQL query that will, for all...

17 Dec 2020

Percentage Of Users Attended A Contest Problem

LeetCode 1633. Write an SQL query to find the percentage...

17 Dec 2020

Fix Names In A Table Problem

LeetCode 1667. Write an SQL query to fix the names...

17 Dec 2020

Duplicate Emails Problem

LeetCode 182. Write a SQL query to find all duplicate...

17 Dec 2020

Customers Who Never Order Problem

LeetCode 183. Write a SQL query to find all customers...

17 Dec 2020

Consecutive Numbers Problem

LeetCode 180. Write an SQL query to find all numbers...

17 Dec 2020

Average Time Of Process Per Machine Problem

LeetCode 1661. There is a factory website that has several...

17 Dec 2020

Second Highest Salary Problem

LeetCode 176. Given the Employee table, write a SQL query...

16 Dec 2020

Employees Earning More Than Their Managers Problem

LeetCode 181. Given the Employee table, write a SQL query...

16 Dec 2020

Bank Account Summary II Problem

LeetCode 1587. Write an SQL query to report the name...

16 Dec 2020

Group Sold Products By The Date Problem

LeetCode 1484. Write an SQL query to find for each...

15 Dec 2020

All Valid Triplets That Can Represent A Country Problem

LeetCode 1623. Write an SQL query to find all the...

15 Dec 2020

Warehouse Manager Problem

LeetCode 1571. Write an SQL query to report how much...

13 Dec 2020

Students With Invalid Departments Problem

LeetCode 1350. Write an SQL query to find the id...

13 Dec 2020

Replace Employee ID With The Unique Identifier Problem

LeetCode 1378. Write an SQL query to show the unique...

13 Dec 2020

Patients With A Condition Problem

LeetCode 1527. Write an SQL query to report the patient_id,...

13 Dec 2020

Invalid Tweets Problem

LeetCode 1683. Write an SQL query to find the IDs...

13 Dec 2020

Find The Team Size Problem

LeetCode 1303. Write an SQL query to find the team...

13 Dec 2020

Combine Two Tables Problem

LeetCode 175. Write a SQL query for a report that...

13 Dec 2020

Maximum Equal Frequency Problem

LeetCode 1224. Given an array nums of positive integers, return...

08 Dec 2020

Number of Islands Problem

LeetCode 200. Given an m x n 2d grid map...

02 Dec 2020

Merge Intervals Problem

LeetCode 56. Given an array of intervals, merge all overlapping...

02 Dec 2020

Longest Continuous Subarray With Absolute Diff Less Than Or Equal To Limit Problem

LeetCode 1438. Given an array of integers nums and an...

02 Dec 2020

Diameter of Binary Tree Problem

LeetCode 543. Given a binary tree, compute the diameter of...

02 Dec 2020

Reverse Linked List Problem

LeetCode 206. Reverse a singly linked list.

26 Nov 2020

Reverse Linked List II Problem

LeetCode 92. Reverse a linked list from position m to...

26 Nov 2020

Palindrome Linked List Problem

LeetCode 234. Given a singly linked list, determine if it’s...

26 Nov 2020

Merge K Sorted Lists Problem

LeetCode 23. You are given an array of k linked-lists...

26 Nov 2020

Merge Two Sorted Lists Problem

LeetCode 21. Merge two sorted linked lists and return a...

25 Nov 2020

Median of Two Sorted Arrays Problem

LeetCode 4. Given two sorted arrays nums1 and nums2 of...

20 Nov 2020

Valid Perfect Square Problem

LeetCode 367. Given a positive integer num, write a function...

15 Nov 2020

Sqrt(x) Problem

LeetCode 69. Given a non-negative integer x, compute and return...

15 Nov 2020

Search Insert Position Problem

LeetCode 35. Given a sorted array of distinct integers and...

15 Nov 2020

Stream of Characters Problem

LeetCode 1032. Implement the StreamChecker class as follows. Constructor, initialize...

14 Nov 2020

Maximum XOR of Two Numbers in an Array Problem

LeetCode 421. Given an integer array nums, return the maximum...

14 Nov 2020

Implement Trie (Prefix Tree) Problem

LeetCode 208. Implement a Trie with insert, search, and startsWith...

14 Nov 2020

Camelcase Matching Problem

LeetCode 1023. A query word matches a given pattern if...

14 Nov 2020

Word Search II Problem

LeetCode 212. Given an m x n board of characters...

12 Nov 2020

Two Sum Input Array Is Sorted Problem

LeetCode 167. Given an array of integers nums sorted in...

12 Nov 2020

Subarray Sum Divisible By K Problem

LeetCode 974. Given an array of integers nums and an...

12 Nov 2020

Replace Words Problem

LeetCode 648. Given a dictionary consisting of many roots, and...

12 Nov 2020

Longest Word In Dictionary Problem

LeetCode 720. Given a list of strings words representing an...

12 Nov 2020

Four Sum II Problem

LeetCode 454. Given four lists A, B, C, D of...

12 Nov 2020

Continuous Subarray Sum Problem

LeetCode 523. Given an array of non-negative integers nums and...

12 Nov 2020

Concatenate Words Problem

LeetCode 472. Given a list of words (without duplicates), return...

12 Nov 2020

Two Sum Less Than K Problem

LeetCode 1099. Given an array of integers nums and an...

11 Nov 2020

Subarray Sum Equals K Problem

LeetCode 560. Given an array of integers nums and an...

11 Nov 2020

Subarray Product Less Than K Problem

LeetCode 713. Given an array of positive integers nums and...

11 Nov 2020

Three Sum Problem

LeetCode 15. Given an array of integers nums, return all...

10 Nov 2020

Four Sum Problem

LeetCode 18. Given an array of integers nums and an...

10 Nov 2020

Two Sum Problem

LeetCode 1. Given an array of integers nums and an...

09 Nov 2020

Tag Two Pointer

Palindrome Linked List Problem

LeetCode 234. Given a singly linked list, determine if it’s...

26 Nov 2020

Two Sum Input Array Is Sorted Problem

LeetCode 167. Given an array of integers nums sorted in...

12 Nov 2020

Two Sum Less Than K Problem

LeetCode 1099. Given an array of integers nums and an...

11 Nov 2020

Subarray Product Less Than K Problem

LeetCode 713. Given an array of positive integers nums and...

11 Nov 2020

Three Sum Problem

LeetCode 15. Given an array of integers nums, return all...

10 Nov 2020

Four Sum Problem

LeetCode 18. Given an array of integers nums and an...

10 Nov 2020

Tag Trie

Short Encoding Of Words Problem

LeetCode 820. A valid encoding of an array of words...

01 Oct 2022

Top K Frequent Words Problem

LeetCode 692. Given an array of strings words and an...

28 Sep 2022

Prefix And Suffix Search Problem

LeetCode 745. Design a special dictionary with some words that...

27 Sep 2022

Number Of Matching Subsequences Problem

LeetCode 792. Given a string s and an array of...

27 Sep 2022

Map Sum Pairs Problem

LeetCode 677. Design a map that allows you to do...

26 Sep 2022

Implement Magic Dictionary Problem

LeetCode 676. Design a data structure that is initialized with...

26 Sep 2022

Palindrome Pairs Problem

LeetCode 336. Given a list of unique words, return all...

16 Sep 2022

Lexicographical Numbers Problem

LeetCode 386. Given an integer n, return all the numbers...

10 Apr 2022

Design Add And Search Words Data Structure Problem

LeetCode 211. Design a data structure that supports adding new...

10 Apr 2022

Word Break Problem

LeetCode 139. Given a string s and a dictionary of...

03 Dec 2021

Word Break II Problem

LeetCode 140. Given a string s and a dictionary of...

03 Dec 2021

Stream of Characters Problem

LeetCode 1032. Implement the StreamChecker class as follows. Constructor, initialize...

14 Nov 2020

Maximum XOR of Two Numbers in an Array Problem

LeetCode 421. Given an integer array nums, return the maximum...

14 Nov 2020

Implement Trie (Prefix Tree) Problem

LeetCode 208. Implement a Trie with insert, search, and startsWith...

14 Nov 2020

Camelcase Matching Problem

LeetCode 1023. A query word matches a given pattern if...

14 Nov 2020

Word Search II Problem

LeetCode 212. Given an m x n board of characters...

12 Nov 2020

Replace Words Problem

LeetCode 648. Given a dictionary consisting of many roots, and...

12 Nov 2020

Longest Word In Dictionary Problem

LeetCode 720. Given a list of strings words representing an...

12 Nov 2020

Concatenate Words Problem

LeetCode 472. Given a list of words (without duplicates), return...

12 Nov 2020

Number of Islands Problem

LeetCode 200. Given an m x n 2d grid map...

02 Dec 2020

Diameter of Binary Tree Problem

LeetCode 543. Given a binary tree, compute the diameter of...

02 Dec 2020

Longest Word In Dictionary Problem

LeetCode 720. Given a list of strings words representing an...

12 Nov 2020

Concatenate Words Problem

LeetCode 472. Given a list of words (without duplicates), return...

12 Nov 2020

Tag Backtracking

Unique Paths III Problem

LeetCode 980. You are given an m x n integer...

01 Oct 2022

Split Array Into Fibonacci Sequence Problem

LeetCode 842. You are given a string of digits num,...

01 Oct 2022

Numbers With Same Consecutive Differences Problem

LeetCode 967. Return all non-negative integers of length n such...

01 Oct 2022

Number Of Squareful Arrays Problem

LeetCode 996. An array is squareful if the sum of...

01 Oct 2022

Ambiguous Coordinates Problem

LeetCode 816. We had some 2-dimensional coordinates, like “(1, 3)”...

30 Sep 2022

Stickers To Spell Word Problem

LeetCode 691. We are given n different types of stickers....

28 Sep 2022

Shopping Offers Problem

LeetCode 638. In LeetCode Store, there are n items to...

28 Sep 2022

Partition To K Equal Sum Subsets Problem

LeetCode 698. Given an integer array nums and an integer...

27 Sep 2022

Letter Case Permutation Problem

LeetCode 784. Given a string s, we can transform every...

27 Sep 2022

All Paths From Source To Target Problem

LeetCode 797. Given a directed acyclic graph (DAG) of n...

26 Sep 2022

24 Game Problem

LeetCode 679. You are given an integer array cards of...

26 Sep 2022

Target Sum Problem

LeetCode 494. You are given an integer array nums and...

24 Sep 2022

Matchsticks To Square Problem

LeetCode 473. You are given an integer array matchsticks where...

22 Sep 2022

Increasing Subsequences Problem

LeetCode 491. Given an integer array nums, return all the...

22 Sep 2022

Binary Watch Problem

LeetCode 401. A binary watch has 4 LEDs on the...

19 Sep 2022

Beautiful Arrangement Problem

LeetCode 526. Suppose you have n integers labeled 1 through...

19 Sep 2022

Remove Invalid Parentheses Problem

LeetCode 301. Given a string s that contains parentheses and...

18 Sep 2022

Expression Add Operators Problem

LeetCode 282. Given a string num that contains only digits...

10 Apr 2022

Count Numbers With Unique Digits Problem

LeetCode 357. Given an integer n, return the count of...

10 Apr 2022

Combination Sum III Problem

LeetCode 216. Find all valid combinations of k numbers that...

10 Apr 2022

Binary Tree Paths Problem

LeetCode 257. Given the root of a binary tree, return...

10 Apr 2022

Additive Number Problem

LeetCode 306. Additive number is a string whose digits can...

10 Apr 2022

Word Break II Problem

LeetCode 140. Given a string s and a dictionary of...

03 Dec 2021

Palindrome Partitioning Problem

LeetCode 131. Given a string s, partition s such that...

03 Dec 2021

Word Ladder II Problem

LeetCode 126. Given two words, beginWord and endWord, and a...

29 Nov 2021

Word Search Problem

LeetCode 79. Given an m x n grid of characters...

14 Nov 2021

Unique Binary Search Trees II Problem

LeetCode 95. Given an integer n, return all the structurally...

14 Nov 2021

Subsets Problem

LeetCode 78. Given an integer array nums of unique elements,...

14 Nov 2021

Subsets II Problem

LeetCode 90. Given an integer array nums that may contain...

14 Nov 2021

Restore IP Addresses Problem

LeetCode 93. Given a string s containing only digits, return...

14 Nov 2021

Gray Code Problem

LeetCode 89. Given an integer n, return any valid n-bit...

14 Nov 2021

Combinations Problem

LeetCode 77. Given two integers n and k, return all...

10 Nov 2021

N-Queens Problem

LeetCode 51. Given an integer n, return all distinct solutions...

08 Nov 2021

N-Queens II Problem

LeetCode 52. Given an integer n, return the number of...

08 Nov 2021

Sudoku Solver Problem

LeetCode 37. Write a program to solve a Sudoku puzzle...

06 Nov 2021

Permutations Problem

LeetCode 46. Given an array nums of distinct integers, return...

06 Nov 2021

Permutations II Problem

LeetCode 47. Given a collection of numbers, nums, that might...

06 Nov 2021

Combination Sum Problem

LeetCode 39. Given an array of distinct integers candidates and...

06 Nov 2021

Combination Sum II Problem

LeetCode 40. Given a collection of candidate numbers (candidates) and...

06 Nov 2021

Letter Combinations of a Phone Number Problem

LeetCode 17. Given a string containing digits from 2-9 inclusive,...

05 Nov 2021

Generate Parentheses Problem

LeetCode 22. Given n pairs of parentheses, write a function...

05 Nov 2021

Word Search II Problem

LeetCode 212. Given an m x n board of characters...

12 Nov 2020

Tag Greedy

String Without Aaa Or Bbb Problem

LeetCode 984. Given two integers a and b, return any...

01 Oct 2022

Stamping The Sequence Problem

LeetCode 936. You are given two strings stamp and target....

01 Oct 2022

Smallest Range II Problem

LeetCode 910. You are given an integer array nums and...

01 Oct 2022

Score After Flipping Matrix Problem

LeetCode 861. You are given an m x n binary...

01 Oct 2022

Pancake Sorting Problem

LeetCode 969. Given an array of integers arr, sort the...

01 Oct 2022

Most Profit Assigning Work Problem

LeetCode 826. You have n jobs and m workers. You...

01 Oct 2022

Minimum Number Of Refueling Stops Problem

LeetCode 871. A car travels from a starting position to...

01 Oct 2022

Minimum Increment To Make Array Unique Problem

LeetCode 945. You are given an integer array nums. In...

01 Oct 2022

Minimum Cost To Hire K Workers Problem

LeetCode 857. There are n workers. You are given two...

01 Oct 2022

Minimum Add To Make Parentheses Valid Problem

LeetCode 921. A parentheses string is valid if and only...

01 Oct 2022

Max Increase To Keep City Skyline Problem

LeetCode 807. There is a city composed of n x...

01 Oct 2022

Lemonade Change Problem

LeetCode 860. At a lemonade stand, each lemonade costs $5....

01 Oct 2022

Largest Perimeter Triangle Problem

LeetCode 976. Given an integer array nums, return the largest...

01 Oct 2022

Hand Of Straights Problem

LeetCode 846. Alice has some number of cards and she...

01 Oct 2022

DI String Match Problem

LeetCode 942. A permutation perm of n + 1 integers...

01 Oct 2022

Delete Columns To Make Sorted II Problem

LeetCode 955. You are given an array of n strings...

01 Oct 2022

Broken Calculator Problem

LeetCode 991. There is a broken calculator that has the...

30 Sep 2022

Boats To Save People Problem

LeetCode 881. You are given an array people where people[i]...

30 Sep 2022

Bag Of Tokens Problem

LeetCode 948. You have an initial power of power, an...

30 Sep 2022

Array Of Doubled Pairs Problem

LeetCode 954. Given an integer array of even length arr,...

30 Sep 2022

Advantage Shuffle Problem

LeetCode 870. You are given two integer arrays nums1 and...

30 Sep 2022

Valid Triangle Number Problem

LeetCode 611. Given an integer array nums, return the number...

28 Sep 2022

Valid Parenthesis String Problem

LeetCode 678. Given a string s containing only three types...

28 Sep 2022

Valid Palindrome II Problem

LeetCode 680. Given a string s, return true if the...

28 Sep 2022

Task Scheduler Problem

LeetCode 621. Given a characters array tasks, representing the tasks...

28 Sep 2022

Set Intersection Size At Least Two Problem

LeetCode 757. You are given a 2D integer array intervals...

28 Sep 2022

Reorganize String Problem

LeetCode 767. Given a string s, rearrange the characters of...

28 Sep 2022

Rabbits In Forest Problem

LeetCode 781. There is a forest with an unknown number...

28 Sep 2022

Partition Labels Problem

LeetCode 763. You are given a string s. We want...

28 Sep 2022

Dota2 Senate Problem

LeetCode 649. In the world of Dota2, there are two...

28 Sep 2022

Split Array Into Consecutive Subsequences Problem

LeetCode 659. You are given an integer array nums that...

27 Sep 2022

Smallest Range Covering Elements From K Lists Problem

LeetCode 632. You have k lists of sorted integers in...

27 Sep 2022

Monotone Increasing Digits Problem

LeetCode 738. An integer has monotone increasing digits if and...

27 Sep 2022

Maximum Length Of Pair Chain Problem

LeetCode 646. You are given an array of n pairs...

27 Sep 2022

Max Chunks To Make Sorted Problem

LeetCode 769. You are given an integer array arr of...

27 Sep 2022

Max Chunks To Make Sorted II Problem

LeetCode 768. You are given an integer array arr.

27 Sep 2022

Maximum Swap Problem

LeetCode 670. You are given an integer num. You can...

26 Sep 2022

Course Schedule III Problem

LeetCode 630. There are n different online courses numbered from...

26 Sep 2022

Couples Holding Hands Problem

LeetCode 765. There are n couples sitting in 2n seats...

26 Sep 2022

Can Place Flowers Problem

LeetCode 605. You have a long flowerbed in which some...

26 Sep 2022

Best Time To Buy And Sell Stock With Transaction Fee Problem

LeetCode 714. You are given an array prices where prices[i]...

26 Sep 2022

Super Washing Machines Problem

LeetCode 517. You have n super washing machines on a...

25 Sep 2022

Strong Password Checker Problem

LeetCode 420. A password is considered strong if the below...

25 Sep 2022

IPO Problem

LeetCode 502. Suppose LeetCode will start its IPO soon. In...

25 Sep 2022

Split Array Largest Sum Problem

LeetCode 410. Given an array nums which consists of non-negative...

24 Sep 2022

Shortest Unsorted Continuous Subarray Problem

LeetCode 581. Given an integer array nums, you need to...

24 Sep 2022

Remove K Digits Problem

LeetCode 402. Given string num representing a non-negative integer num,...

24 Sep 2022

Queue Reconstruction By Height Problem

LeetCode 406. You are given an array of people, people,...

24 Sep 2022

Non-Overlapping Intervals Problem

LeetCode 435. Given an array of intervals intervals where intervals[i]...

23 Sep 2022

Minimum Number Of Arrows To Burst Balloons Problem

LeetCode 452. There are some spherical balloons taped onto a...

23 Sep 2022

Longest Palindrome Problem

LeetCode 409. Given a string s which consists of lowercase...

22 Sep 2022

Assign Cookies Problem

LeetCode 455. Assume you are an awesome parent and want...

19 Sep 2022

Array Partition I Problem

LeetCode 561. Given an integer array nums of 2n integers,...

19 Sep 2022

Wiggle Subsequence Problem

LeetCode 376. A wiggle sequence is a sequence where the...

18 Sep 2022

Remove Duplicate Letters Problem

LeetCode 316. Given a string s, remove duplicate letters so...

18 Sep 2022

Patching Array Problem

LeetCode 330. Given a sorted integer array nums and an...

16 Sep 2022

Integer Replacement Problem

LeetCode 397. Given a positive integer n,you can apply one...

10 Apr 2022

Increasing Triplet Subsequence Problem

LeetCode 334. Given an integer array nums, return true if...

10 Apr 2022

Create Maximum Number Problem

LeetCode 321. You are given two integer arrays nums1 and...

10 Apr 2022

Largest Number Problem

LeetCode 179. Given a list of non-negative integers nums, arrange...

04 Dec 2021

Gas Station Problem

LeetCode 134. There are n gas stations along a circular...

03 Dec 2021

Candy Problem

LeetCode 135. There are n children standing in a line....

03 Dec 2021

Best Time To Buy And Sell Stock Ii Problem

LeetCode 122. You are given an integer array prices where...

29 Nov 2021

Jump Game Problem

LeetCode 55. Given an m x n matrix, return all...

08 Nov 2021

Wildcard Matching Problem

LeetCode 44. Write the code that will take a string...

06 Nov 2021

Jump Game II Problem

LeetCode 45. Given an array of non-negative integers nums, you...

06 Nov 2021

Container With Most Water Problem

LeetCode 11. Given n non-negative integers a_1, a_2, …, a_n...

05 Nov 2021

Maximum XOR of Two Numbers in an Array Problem

LeetCode 421. Given an integer array nums, return the maximum...

14 Nov 2020

Tag Queue

Stamping The Sequence Problem

LeetCode 936. You are given two strings stamp and target....

01 Oct 2022

Shortest Subarray With Sum At Least K Problem

LeetCode 862. Given an integer array nums and an integer...

01 Oct 2022

Reveal Cards In Increasing Order Problem

LeetCode 950. You are given an integer array deck. There...

01 Oct 2022

Number Of Recent Calls Problem

LeetCode 933. You have a RecentCounter class which counts the...

01 Oct 2022

Minimum Number Of K Consecutive Bit Flips Problem

LeetCode 995. You are given a binary array nums and...

01 Oct 2022

Maximum Sum Circular Subarray Problem

LeetCode 918. Given a circular integer array nums of length...

01 Oct 2022

Dota2 Senate Problem

LeetCode 649. In the world of Dota2, there are two...

28 Sep 2022

Design Circular Queue Problem

LeetCode 622. Design your implementation of the circular queue. The...

27 Sep 2022

Design Circular Deque Problem

LeetCode 641. Design your implementation of the circular double-ended queue...

27 Sep 2022

Sliding Window Maximum Problem

LeetCode 239. You are given an array of integersnums, there...

18 Sep 2022

Implement Stack Using Queues Problem

LeetCode 225. Implement a last-in-first-out (LIFO) stack using only two...

10 Apr 2022

Implement Queue Using Stacks Problem

LeetCode 232. Implement a first in first out (FIFO) queue...

10 Apr 2022

Flatten Nested List Iterator Problem

LeetCode 341. You are given a nested list of integers...

10 Apr 2022

First Unique Character In A String Problem

LeetCode 387. Given a string s, find the first non-repeating...

10 Apr 2022

Number of Islands Problem

LeetCode 200. Given an m x n 2d grid map...

02 Dec 2020

Longest Continuous Subarray With Absolute Diff Less Than Or Equal To Limit Problem

LeetCode 1438. Given an array of integers nums and an...

02 Dec 2020

Stream of Characters Problem

LeetCode 1032. Implement the StreamChecker class as follows. Constructor, initialize...

14 Nov 2020

Time Based Key-Value Store Problem

LeetCode 981. Design a time-based key-value data structure that can...

01 Oct 2022

Super Egg Drop Problem

LeetCode 887. You are given k identical eggs and you...

01 Oct 2022

Shortest Subarray With Sum At Least K Problem

LeetCode 862. Given an integer array nums and an integer...

01 Oct 2022

Peak Index In A Mountain Array Problem

LeetCode 852. Let’s call an array arr a mountainif the...

01 Oct 2022

Online Election Problem

LeetCode 911. You are given two integer arrays persons and...

01 Oct 2022

Numbers At Most N Given Digit Set Problem

LeetCode 902. Given an array of digits which is sorted...

01 Oct 2022

Nth Magical Number Problem

LeetCode 878. A positive integer is magical if it is...

01 Oct 2022

Most Profit Assigning Work Problem

LeetCode 826. You have n jobs and m workers. You...

01 Oct 2022

Koko Eating Bananas Problem

LeetCode 875. Koko loves to eat bananas. There are n...

01 Oct 2022

Friends Of Appropriate Ages Problem

LeetCode 825. There are n persons on a social media...

01 Oct 2022

Fair Candy Swap Problem

LeetCode 888. Alice and Bob have a different total number...

01 Oct 2022

Valid Triangle Number Problem

LeetCode 611. Given an integer array nums, return the number...

28 Sep 2022

Swim In Rising Water Problem

LeetCode 778. You are given an n x n integer...

28 Sep 2022

Random Pick With Blacklist Problem

LeetCode 710. You are given an integer n and an...

28 Sep 2022

Preimage Size Of Factorial Zeroes Function Problem

LeetCode 793. Let f(x) be the number of zeroes at...

28 Sep 2022

My Calendar III Problem

LeetCode 732. A k-booking happens when k events have some...

28 Sep 2022

My Calendar II Problem

LeetCode 731. You are implementing a program to use as...

28 Sep 2022

My Calendar I Problem

LeetCode 729. You are implementing a program to use as...

28 Sep 2022

Sum Of Square Numbers Problem

LeetCode 633. Given a non-negative integer c, decide whether there’re...

27 Sep 2022

Reach A Number Problem

LeetCode 754. You are standing at position 0 on an...

27 Sep 2022

Maximum Length Of Repeated Subarray Problem

LeetCode 718. Given two integer arrays nums1 and nums2, return...

27 Sep 2022

Kth Smallest Number In Multiplication Table Problem

LeetCode 668. Nearly everyone has used the Multiplication Table. The...

27 Sep 2022

Find Smallest Letter Greater Than Target Problem

LeetCode 744. Given a characters array letters that is sorted...

27 Sep 2022

K-Th Smallest Prime Fraction Problem

LeetCode 786. You are given a sorted integer array arr...

26 Sep 2022

Find K-Th Smallest Pair Distance Problem

LeetCode 719. The distance of a pair of integers a...

26 Sep 2022

Find K Closest Elements Problem

LeetCode 658. Given a sorted integer array arr, two integers...

26 Sep 2022

Binary Search Problem

LeetCode 704. Given an array of integers nums which is...

26 Sep 2022

Random Point In Non-Overlapping Rectangles Problem

LeetCode 497. You are given an array of non-overlapping axis-aligned...

25 Sep 2022

Split Array Largest Sum Problem

LeetCode 410. Given an array nums which consists of non-negative...

24 Sep 2022

Smallest Good Base Problem

LeetCode 483. Given an integer n represented as a string,...

24 Sep 2022

Single Element In A Sorted Array Problem

LeetCode 540. You are given a sorted array consisting of...

24 Sep 2022

Reverse Pairs Problem

LeetCode 493. Given an integer array nums, return the number...

24 Sep 2022

Random Pick With Weight Problem

LeetCode 528. You are given a 0-indexed array of positive...

24 Sep 2022

Most Frequent Subtree Sum Problem

LeetCode 508. Given the root of a binary tree, return...

23 Sep 2022

K-Diff Pairs In An Array Problem

LeetCode 532. Given an array of integers nums and an...

22 Sep 2022

Heaters Problem

LeetCode 475. Winter is coming! During the contest, your first...

22 Sep 2022

Arranging Coins Problem

LeetCode 441. You have n coins and you want to...

19 Sep 2022

132 Pattern Problem

LeetCode 456. Given an arrayof n integers nums, a 132...

19 Sep 2022

Search A 2D Matrix II Problem

LeetCode 240. Write an efficient algorithm that searches for a...

18 Sep 2022

Nth Digit Problem

LeetCode 400. Given an integer n, return the n^th digit...

15 Sep 2022

Missing Number Problem

LeetCode 268. Given an array nums containing n distinct numbers...

15 Sep 2022

Minimum Size Subarray Sum Problem

LeetCode 209. Given an array of positive integers nums and...

15 Sep 2022

Longest Increasing Subsequence Problem

LeetCode 300. Given an integer array nums, return the length...

10 Apr 2022

Kth Smallest Element In A Sorted Matrix Problem

LeetCode 378. Given an n x n matrix where each...

10 Apr 2022

Intersection Of Two Arrays II Problem

LeetCode 350. Given two integer arrays nums1 and nums2, return...

10 Apr 2022

H-Index II Problem

LeetCode 275. Given an array of integers citations where citations[i]...

10 Apr 2022

Guess Number Higher Or Lower Problem

LeetCode 374. We are playing the Guess Game. The game...

10 Apr 2022

First Bad Version Problem

LeetCode 278. You are a product manager and currently leading...

10 Apr 2022

Find The Duplicate Number Problem

LeetCode 287. Given an array of integers nums containingn +...

10 Apr 2022

Data Stream As Disjoint Intervals Problem

LeetCode 352. Given a data stream input of non-negative integers...

10 Apr 2022

Count Of Smaller Numbers After Self Problem

LeetCode 315. You are given an integer array nums and...

10 Apr 2022

Count Of Range Sum Problem

LeetCode 327. Given an integer array nums and two integers...

10 Apr 2022

Count Complete Tree Nodes Problem

LeetCode 222. Given the root of a complete binary tree,...

10 Apr 2022

Find Peak Element Problem

LeetCode 162. A peak element is an element that is...

04 Dec 2021

Find Minimum In Rotated Sorted Array Problem

LeetCode 153. Suppose an array of length n sorted in...

04 Dec 2021

Find Minimum In Rotated Sorted Array II Problem

LeetCode 154. Suppose an array of length n sorted in...

04 Dec 2021

Search in Rotated Sorted Array II Problem

LeetCode 81. There is an integer array nums sorted in...

14 Nov 2021

Search A 2D Matrix Problem

LeetCode 74. Write an efficient algorithm that searches for a...

10 Nov 2021

Find First and Last Position of Element in Sorted Array Problem

LeetCode 34. Given the array nums after the possible rotation...

06 Nov 2021

Median of Two Sorted Arrays Problem

LeetCode 4. Given two sorted arrays nums1 and nums2 of...

20 Nov 2020

Valid Perfect Square Problem

LeetCode 367. Given a positive integer num, write a function...

15 Nov 2020

Sqrt(x) Problem

LeetCode 69. Given a non-negative integer x, compute and return...

15 Nov 2020

Search Insert Position Problem

LeetCode 35. Given a sorted array of distinct integers and...

15 Nov 2020

Tag C++

Value Categories in C++

Every C++ expression has a type and belongs to a...

07 Dec 2020

Rvalue References in C++: Perfect Forwarding

Perfect forwarding reduces the need for overloaded functions and helps...

07 Dec 2020

Rvalue References in C++: Move Semantics

The rvalue references enable us to distinguish an lvalue from...

07 Dec 2020

References in C++

A reference is an alias of another object. It stores...

07 Dec 2020

Lvalue References in C++

An lvalue reference is another name of an object. An...

07 Dec 2020

Lambda Expressions in C++

A lambda expression is a convenient way of defining an...

07 Dec 2020

Template Specializations in C++

A template specialization is a separate definition in which the...

03 Dec 2020

Implicit Type Conversions in C++

C++ transforms the operands to a common type before performing...

03 Dec 2020

Explicit Type Conversions in C++

An explicit conversion is also called as a cast. There...

03 Dec 2020

Copy Constructors in C++

The constructor that takes a single parameter that is a...

01 Dec 2020

Inline Functions in C++

A function specified as inline is expanded everywhere it is...

30 Nov 2020

Function Pointers in C++

A function pointer is a pointer that denotes a function...

30 Nov 2020

Online Book Reader System Problem

Design the data structures for an online book reader system...

22 Nov 2020

Parking Lot Problem

Design a parking lot using object-oriented principles. We will focus...

21 Nov 2020

Call Center Problem

An object oriented design problem. Imagine you have a call...

21 Nov 2020

Singleton Design Pattern

The singleton design pattern is a type of creational pattern...

20 Nov 2020

Factory Design Pattern

The factory design pattern is a type of creational pattern...

20 Nov 2020

Weak_Ptr in C++

Sometimes an object must store a way to access the...

19 Nov 2020

Friend Class and Function in C++

A friend class can access private and protected members of...

19 Nov 2020

Unique_Ptr in C++

A unique_ptr does not share its pointer. It cannot be...

18 Nov 2020

Smart Pointers in C++

In modern C++ programming, the Standard Library includes smart pointers,...

18 Nov 2020

Shared_Ptr in C++

The shared_ptr type is a smart pointer that is designed...

18 Nov 2020

Templates in C++

A template is a blueprint or formula for creating a...

17 Nov 2020

Polymorphism in C++

Polymorphism means having more than one function with the same...

16 Nov 2020

Interfaces in C++

An interface describes the behavior or capabilities of a C++...

16 Nov 2020

Tag Interface

Interfaces in C++

An interface describes the behavior or capabilities of a C++...

16 Nov 2020

Tag Abstract Class

Interfaces in C++

An interface describes the behavior or capabilities of a C++...

16 Nov 2020

Tag Pure Virtual Function

Polymorphism in C++

Polymorphism means having more than one function with the same...

16 Nov 2020

Interfaces in C++

An interface describes the behavior or capabilities of a C++...

16 Nov 2020

Tag Concrete Class

Interfaces in C++

An interface describes the behavior or capabilities of a C++...

16 Nov 2020

Tag Polymorphism

Polymorphism in C++

Polymorphism means having more than one function with the same...

16 Nov 2020

Tag Overload

Polymorphism in C++

Polymorphism means having more than one function with the same...

16 Nov 2020

Tag Override

Polymorphism in C++

Polymorphism means having more than one function with the same...

16 Nov 2020

Tag Virtual Function

Polymorphism in C++

Polymorphism means having more than one function with the same...

16 Nov 2020

Tag Template

Template Specializations in C++

A template specialization is a separate definition in which the...

03 Dec 2020

Templates in C++

A template is a blueprint or formula for creating a...

17 Nov 2020

Tag Function Template

Templates in C++

A template is a blueprint or formula for creating a...

17 Nov 2020

Tag Class Template

Templates in C++

A template is a blueprint or formula for creating a...

17 Nov 2020

Tag Smart Pointers

Weak_Ptr in C++

Sometimes an object must store a way to access the...

19 Nov 2020

Unique_Ptr in C++

A unique_ptr does not share its pointer. It cannot be...

18 Nov 2020

Smart Pointers in C++

In modern C++ programming, the Standard Library includes smart pointers,...

18 Nov 2020

Shared_Ptr in C++

The shared_ptr type is a smart pointer that is designed...

18 Nov 2020

Tag RAII

Weak_Ptr in C++

Sometimes an object must store a way to access the...

19 Nov 2020

Unique_Ptr in C++

A unique_ptr does not share its pointer. It cannot be...

18 Nov 2020

Smart Pointers in C++

In modern C++ programming, the Standard Library includes smart pointers,...

18 Nov 2020

Shared_Ptr in C++

The shared_ptr type is a smart pointer that is designed...

18 Nov 2020

Tag Shared_Ptr

Smart Pointers in C++

In modern C++ programming, the Standard Library includes smart pointers,...

18 Nov 2020

Shared_Ptr in C++

The shared_ptr type is a smart pointer that is designed...

18 Nov 2020

Tag Raw Pointers

Smart Pointers in C++

In modern C++ programming, the Standard Library includes smart pointers,...

18 Nov 2020

Tag Unique_Ptr

Unique_Ptr in C++

A unique_ptr does not share its pointer. It cannot be...

18 Nov 2020

Smart Pointers in C++

In modern C++ programming, the Standard Library includes smart pointers,...

18 Nov 2020

Tag Weak_Ptr

Weak_Ptr in C++

Sometimes an object must store a way to access the...

19 Nov 2020

Smart Pointers in C++

In modern C++ programming, the Standard Library includes smart pointers,...

18 Nov 2020

Tag Friend Class

Friend Class and Function in C++

A friend class can access private and protected members of...

19 Nov 2020

Tag Friend Function

Friend Class and Function in C++

A friend class can access private and protected members of...

19 Nov 2020

Tag Cyclic Reference

Weak_Ptr in C++

Sometimes an object must store a way to access the...

19 Nov 2020

Tag Weak Reference

Weak_Ptr in C++

Sometimes an object must store a way to access the...

19 Nov 2020

Tag Factory Pattern

Factory Design Pattern

The factory design pattern is a type of creational pattern...

20 Nov 2020

Tag Creational Pattern

Singleton Design Pattern

The singleton design pattern is a type of creational pattern...

20 Nov 2020

Factory Design Pattern

The factory design pattern is a type of creational pattern...

20 Nov 2020

Tag Singleton Pattern

Call Center Problem

An object oriented design problem. Imagine you have a call...

21 Nov 2020

Singleton Design Pattern

The singleton design pattern is a type of creational pattern...

20 Nov 2020

Tag OOD

Online Book Reader System Problem

Design the data structures for an online book reader system...

22 Nov 2020

Parking Lot Problem

Design a parking lot using object-oriented principles. We will focus...

21 Nov 2020

Call Center Problem

An object oriented design problem. Imagine you have a call...

21 Nov 2020

Tag Linked List

Middle Of The Linked List Problem

LeetCode 876. Given the head of a singly linked list,...

01 Oct 2022

Linked List Components Problem

LeetCode 817. You are given the head of a linked...

01 Oct 2022

Split Linked List In Parts Problem

LeetCode 725. Given the head of a singly linked list...

28 Sep 2022

Design Circular Queue Problem

LeetCode 622. Design your implementation of the circular queue. The...

27 Sep 2022

Design Circular Deque Problem

LeetCode 641. Design your implementation of the circular double-ended queue...

27 Sep 2022

Design Linked List Problem

LeetCode 707. Design your implementation of the linked list. You...

26 Sep 2022

Design Hashset Problem

LeetCode 705. Design a HashSet without using any built-in hash...

26 Sep 2022

Design Hashmap Problem

LeetCode 706. Design a HashMap without using any built-in hash...

26 Sep 2022

LFU Cache Problem

LeetCode 460. Design and implement a data structure for a...

22 Sep 2022

Flatten A Multilevel Doubly Linked List Problem

LeetCode 430. You are given a doubly linked list, which...

21 Sep 2022

All O'One Data Structure Problem

LeetCode 432. Design a data structure to store the strings...

19 Sep 2022

Add Two Numbers II Problem

LeetCode 445. You are given two non-empty linked lists representing...

19 Sep 2022

Remove Linked List Elements Problem

LeetCode 203. Given the head of a linked list and...

18 Sep 2022

Odd Even Linked List Problem

LeetCode 328. Given the head of a singly linked list,...

15 Sep 2022

Linked List Random Node Problem

LeetCode 382. Given a singly linked list, return a random...

10 Apr 2022

Design Twitter Problem

LeetCode 355. Design a simplified version of Twitter where users...

10 Apr 2022

Delete Node In A Linked List Problem

LeetCode 237. Write a function to delete a node in...

10 Apr 2022

Intersection Of Two Linked Lists Problem

LeetCode 160. Given the heads of two singly linked-lists headA...

04 Dec 2021

Sort List Problem

LeetCode 148. Given the head of a linked list, return...

03 Dec 2021

Reorder List Problem

LeetCode 143. You are given the head of a singly...

03 Dec 2021

Lru Cache Problem

LeetCode 146. Design a data structure that follows the constraints...

03 Dec 2021

Linked List Cycle Problem

LeetCode 141. Given head, the head of a linked list,...

03 Dec 2021

Linked List Cycle II Problem

LeetCode 142. Given the head of a linked list, return...

03 Dec 2021

Insertion Sort List Problem

LeetCode 147. Given the head of a singly linked list,...

03 Dec 2021

Copy List With Random Pointer Problem

LeetCode 138. A linked list of length n is given...

03 Dec 2021

Flatten Binary Tree To Linked List Problem

LeetCode 114. Given the root of a binary tree, flatten...

29 Nov 2021

Convert Sorted List To Binary Search Tree Problem

LeetCode 109. Given the head of a singly linked list...

29 Nov 2021

Remove Duplicates from Sorted List Problem

LeetCode 83. Given the head of a sorted linked list,...

14 Nov 2021

Remove Duplicates from Sorted List II Problem

LeetCode 82. Given the head of a sorted linked list,...

14 Nov 2021

Partition List Problem

LeetCode 86. Given the head of a linked list and...

14 Nov 2021

Rotate List Problem

LeetCode 61. Given the head of a linked list, rotate...

09 Nov 2021

Reverse Nodes in k-Group Problem

LeetCode 25. Given a linked list, reverse the nodes of...

06 Nov 2021

Swap Nodes in Pairs Problem

LeetCode 24. Given a linked list, swap every two adjacent...

05 Nov 2021

Remove Nth Node From End of List Problem

LeetCode 19. Given the head of a linked list, remove...

05 Nov 2021

Add Two Numbers Problem

LeetCode 2. You are given two non-empty linked lists representing...

05 Mar 2021

Reverse Linked List Problem

LeetCode 206. Reverse a singly linked list.

26 Nov 2020

Reverse Linked List II Problem

LeetCode 92. Reverse a linked list from position m to...

26 Nov 2020

Palindrome Linked List Problem

LeetCode 234. Given a singly linked list, determine if it’s...

26 Nov 2020

Merge K Sorted Lists Problem

LeetCode 23. You are given an array of k linked-lists...

26 Nov 2020

Merge Two Sorted Lists Problem

LeetCode 21. Merge two sorted linked lists and return a...

25 Nov 2020

Tag Priority Queue

Merge K Sorted Lists Problem

LeetCode 23. You are given an array of k linked-lists...

26 Nov 2020

Tag Virtual Memory

Virtual Memory VIII: Page Replacement Policies

How can the OS decide which page(s) to evict from...

29 Nov 2020

Virtual Memory VII: Page Replacement Mechanisms

How can the OS make use of a larger, slower...

29 Nov 2020

Virtual Memory VI: Smaller Tables

How can we make page tables smaller.

29 Nov 2020

Virtual Memory V: TLBs

How can we speed up address translation, and generally avoid...

29 Nov 2020

Virtual Memory IV: Paging

How can we virtualize memory with pages, so as to...

28 Nov 2020

Virtual Memory III: Segmentation

How to support a large address space with (potentially) a...

27 Nov 2020

Virtual Memory II: Address Translation

How can we relocate the process in memory in a...

27 Nov 2020

Virtual Memory I: Overview

Virtual Memory is an abstraction that the Operating System provides...

26 Nov 2020

Tag Function Pointers

Function Pointers in C++

A function pointer is a pointer that denotes a function...

30 Nov 2020

Tag Pointers to Functions

Function Pointers in C++

A function pointer is a pointer that denotes a function...

30 Nov 2020

Tag Inline Functions

Inline Functions in C++

A function specified as inline is expanded everywhere it is...

30 Nov 2020

Tag Process

Process I: The Abstraction

How can the OS provide the illusion of nearly-endless supply...

30 Nov 2020

Tag Copy Constructors

Copy Constructors in C++

The constructor that takes a single parameter that is a...

01 Dec 2020

Tag Tree

Vertical Order Traversal Of A Binary Tree Problem

LeetCode 987. Given the root of a binary tree, calculate...

01 Oct 2022

Univalued Binary Tree Problem

LeetCode 965. A binary tree is uni-valued if every node...

01 Oct 2022

Sum Of Distances In Tree Problem

LeetCode 834. There is an undirected connected tree with n...

01 Oct 2022

Smallest Subtree With All The Deepest Nodes Problem

LeetCode 865. Given the root of a binary tree, the...

01 Oct 2022

Smallest String Starting From Leaf Problem

LeetCode 988. You are given the root of a binary...

01 Oct 2022

Range Sum Of BST Problem

LeetCode 938. Given the root node of a binary search...

01 Oct 2022

Maximum Binary Tree II Problem

LeetCode 998. A maximum tree is a tree where every...

01 Oct 2022

Leaf-Similar Trees Problem

LeetCode 872. Consider all the leaves of a binary tree,...

01 Oct 2022

Increasing Order Search Tree Problem

LeetCode 897. Given the root of a binary search tree,...

01 Oct 2022

Flip Equivalent Binary Trees Problem

LeetCode 951. For a binary tree T, we can define...

01 Oct 2022

Flip Binary Tree To Match Preorder Traversal Problem

LeetCode 971. You are given the root of a binary...

01 Oct 2022

Distribute Coins In Binary Tree Problem

LeetCode 979. You are given the root of a binary...

01 Oct 2022

Cousins In Binary Tree Problem

LeetCode 993. Given the root of a binary tree with...

01 Oct 2022

Construct Binary Tree From Preorder And Postorder Traversal Problem

LeetCode 889. Given two integer arrays, preorder and postorder where...

30 Sep 2022

Complete Binary Tree Inserter Problem

LeetCode 919. A complete binary tree is a binary tree...

30 Sep 2022

Check Completeness Of A Binary Tree Problem

LeetCode 958. Given the root of a binary tree, determine...

30 Sep 2022

Binary Tree Pruning Problem

LeetCode 814. Given the root of a binary tree, return...

30 Sep 2022

Binary Tree Cameras Problem

LeetCode 968. You are given the root of a binary...

30 Sep 2022

All Possible Full Binary Trees Problem

LeetCode 894. Given an integer n, return a list of...

30 Sep 2022

All Nodes Distance K In Binary Tree Problem

LeetCode 863. Given the root of a binary tree, the...

30 Sep 2022

Two Sum IV - Input Is A BST Problem

LeetCode 653. Given the root of a Binary Search Tree...

27 Sep 2022

Trim A Binary Search Tree Problem

LeetCode 669. Given the root of a binary search tree...

27 Sep 2022

Second Minimum Node In A Binary Tree Problem

LeetCode 671. Given a non-empty special binary tree consisting of...

27 Sep 2022

Search In A Binary Search Tree Problem

LeetCode 700. You are given the root of a binary...

27 Sep 2022

Print Binary Tree Problem

LeetCode 655. Given the root of a binary tree, construct...

27 Sep 2022

Minimum Distance Between BST Nodes Problem

LeetCode 783. Given the root of a Binary Search Tree...

27 Sep 2022

Merge Two Binary Trees Problem

LeetCode 617. You are given two binary trees root1 and...

27 Sep 2022

Maximum Width Of Binary Tree Problem

LeetCode 662. Given the root of a binary tree, return...

27 Sep 2022

Longest Univalue Path Problem

LeetCode 687. Given the root of a binary tree, return...

27 Sep 2022

Maximum Binary Tree Problem

LeetCode 654. You are given an integer array nums with...

26 Sep 2022

Kth Largest Element In A Stream Problem

LeetCode 703. Design a class to find the k^th largest...

26 Sep 2022

Insert Into A Binary Search Tree Problem

LeetCode 701. You are given the root node of a...

26 Sep 2022

Find Duplicate Subtrees Problem

LeetCode 652. Given the rootof a binary tree, return all...

26 Sep 2022

Construct String From Binary Tree Problem

LeetCode 606. Given the root of a binary tree, construct...

26 Sep 2022

Average Of Levels In Binary Tree Problem

LeetCode 637. Given the root of a binary tree, return...

26 Sep 2022

Add One Row To Tree Problem

LeetCode 623. Given the root of a binary tree and...

26 Sep 2022

Sum Of Left Leaves Problem

LeetCode 404. Given the root of a binary tree, return...

24 Sep 2022

Subtree Of Another Tree Problem

LeetCode 572. Given the roots of two binary trees root...

24 Sep 2022

Serialize And Deserialize BST Problem

LeetCode 449. Serialization is converting a data structure or object...

24 Sep 2022

Path Sum III Problem

LeetCode 437. Given the root of a binary tree and...

23 Sep 2022

N-Ary Tree Preorder Traversal Problem

LeetCode 589. Given the root of an n-ary tree, return...

23 Sep 2022

N-Ary Tree Postorder Traversal Problem

LeetCode 590. Given the root of an n-ary tree, return...

23 Sep 2022

N-Ary Tree Level Order Traversal Problem

LeetCode 429. Given an n-ary tree, return the level order...

23 Sep 2022

Most Frequent Subtree Sum Problem

LeetCode 508. Given the root of a binary tree, return...

23 Sep 2022

Minimum Absolute Difference In BST Problem

LeetCode 530. Given the root of a Binary Search Tree...

22 Sep 2022

Maximum Depth Of N-Ary Tree Problem

LeetCode 559. Given a n-ary tree, find its maximum depth....

22 Sep 2022

Logical Or Of Two Binary Grids Represented As Quad-Trees Problem

LeetCode 558. A Binary Matrix is a matrix in which...

22 Sep 2022

Find Mode In Binary Search Tree Problem

LeetCode 501. Given the root of a binary search tree...

21 Sep 2022

Find Largest Value In Each Tree Row Problem

LeetCode 515. Given the root of a binary tree, return...

21 Sep 2022

Find Bottom Left Tree Value Problem

LeetCode 513. Given the root of a binary tree, return...

21 Sep 2022

Delete Node In A BST Problem

LeetCode 450. Given a root node reference of a BST...

21 Sep 2022

Convert BST To Greater Tree Problem

LeetCode 538. Given the root of a Binary Search Tree...

21 Sep 2022

Construct Quad Tree Problem

LeetCode 427. Given a n * n matrix grid of...

21 Sep 2022

Binary Tree Tilt Problem

LeetCode 563. Given the root of a binary tree, return...

19 Sep 2022

Verify Preorder Serialization Of A Binary Tree Problem

LeetCode 331. One way to serialize a binary tree is...

18 Sep 2022

Serialize And Deserialize Binary Tree Problem

LeetCode 297. Serialization is the process of converting a data...

18 Sep 2022

Lowest Common Ancestor Of A Binary Tree Problem

LeetCode 236. Given a binary tree, find the lowest common...

10 Apr 2022

Lowest Common Ancestor Of A Binary Search Tree Problem

LeetCode 235. Given a binary search tree (BST), find the...

10 Apr 2022

Kth Smallest Element In A BST Problem

LeetCode 230. Given the root of a binary search tree,...

10 Apr 2022

Invert Binary Tree Problem

LeetCode 226. Given the root of a binary tree, invert...

10 Apr 2022

House Robber III Problem

LeetCode 337. The thief has found himself a new place...

10 Apr 2022

Flatten Nested List Iterator Problem

LeetCode 341. You are given a nested list of integers...

10 Apr 2022

Count Complete Tree Nodes Problem

LeetCode 222. Given the root of a complete binary tree,...

10 Apr 2022

Binary Tree Paths Problem

LeetCode 257. Given the root of a binary tree, return...

10 Apr 2022

Binary Tree Right Side View Problem

LeetCode 199. Given the root of a binary tree, imagine...

04 Dec 2021

Binary Search Tree Iterator Problem

LeetCode 173. Implement the BSTIterator class that represents an iterator...

04 Dec 2021

Binary Tree Preorder Traversal Problem

LeetCode 144. Given the root of a binary tree, return...

03 Dec 2021

Binary Tree Postorder Traversal Problem

LeetCode 145. Given the root of abinary tree, return the...

03 Dec 2021

Sum Root To Leaf Numbers Problem

LeetCode 129. You are given the root of a binary...

29 Nov 2021

Populating Next Right Pointers In Each Node Problem

LeetCode 116. You are given a perfect binary tree where...

29 Nov 2021

Populating Next Right Pointers In Each Node II Problem

LeetCode 117. Given a binary tree, populate each next pointer...

29 Nov 2021

Path Sum Problem

LeetCode 112. Given the root of a binary tree and...

29 Nov 2021

Path Sum II Problem

LeetCode 113. Given the root of a binary tree and...

29 Nov 2021

Minimum Depth Of Binary Tree Problem

LeetCode 111. Given a binary tree, find its minimum depth....

29 Nov 2021

Flatten Binary Tree To Linked List Problem

LeetCode 114. Given the root of a binary tree, flatten...

29 Nov 2021

Convert Sorted List To Binary Search Tree Problem

LeetCode 109. Given the head of a singly linked list...

29 Nov 2021

Binary Tree Maximum Path Sum Problem

LeetCode 124. A path in a binary tree is a...

29 Nov 2021

Balanced Binary Tree Problem

LeetCode 110. Given a binary tree, determine if it is...

29 Nov 2021

Symmetric Tree Problem

LeetCode 101. Given the root of a binary tree, check...

20 Nov 2021

Maximum Depth of Binary Tree Problem

LeetCode 104. Given the root of a binary tree, return...

20 Nov 2021

Convert Sorted Array to Binary Search Tree Problem

LeetCode 108. Given an integer array nums where the elements...

20 Nov 2021

Construct Binary Tree from Preorder and Inorder Traversal Problem

LeetCode 105. Given two integer arrays preorder and inorder where...

20 Nov 2021

Construct Binary Tree From Inorder And Postorder Traversal Problem

LeetCode 106. Given two integer arrays inorder and postorder where...

20 Nov 2021

Binary Tree Zigzag Level Order Traversal Problem

LeetCode 103. Given the root of a binary tree, return...

20 Nov 2021

Binary Tree Level Order Traversal Problem

LeetCode 102. Given the root of a binary tree, return...

20 Nov 2021

Binary Tree Level Order Traversal II Problem

LeetCode 107. Given the root of a binary tree, return...

20 Nov 2021

Validate Binary Search Tree Problem

LeetCode 98. Given the root of a binary tree, determine...

16 Nov 2021

Same Tree Problem

LeetCode 100. Given the roots of two binary trees p...

16 Nov 2021

Recover Binary Search Tree Problem

LeetCode 99. You are given the root of a binary...

16 Nov 2021

Unique Binary Search Trees Problem

LeetCode 96. Given an integer n, return the number of...

14 Nov 2021

Unique Binary Search Trees II Problem

LeetCode 95. Given an integer n, return all the structurally...

14 Nov 2021

Binary Tree Inorder Traversal Problem

LeetCode 94. Given an m x n grid of characters...

14 Nov 2021

Diameter of Binary Tree Problem

LeetCode 543. Given a binary tree, compute the diameter of...

02 Dec 2020

Tag Sliding Window

Subarrays With K Different Integers Problem

LeetCode 992. Given an integer array nums and an integer...

01 Oct 2022

Shortest Subarray With Sum At Least K Problem

LeetCode 862. Given an integer array nums and an integer...

01 Oct 2022

New 21 Game Problem

LeetCode 837. Alice plays the following game, loosely based on...

01 Oct 2022

Minimum Number Of K Consecutive Bit Flips Problem

LeetCode 995. You are given a binary array nums and...

01 Oct 2022

Longest Turbulent Subarray Problem

LeetCode 978. Given an integer array arr, return the length...

01 Oct 2022

Fruit Into Baskets Problem

LeetCode 904. You are visiting a farm that has a...

01 Oct 2022

Binary Subarrays With Sum Problem

LeetCode 930. Given a binary array nums and an integer...

30 Sep 2022

Smallest Range Covering Elements From K Lists Problem

LeetCode 632. You have k lists of sorted integers in...

27 Sep 2022

Maximum Length Of Repeated Subarray Problem

LeetCode 718. Given two integer arrays nums1 and nums2, return...

27 Sep 2022

Maximum Average Subarray I Problem

LeetCode 643. You are given an integer array nums consisting...

26 Sep 2022

Sliding Window Median Problem

LeetCode 480. The median is the middle value in an...

24 Sep 2022

Permutation In String Problem

LeetCode 567. Given two strings s1 and s2, return true...

24 Sep 2022

Longest Repeating Character Replacement Problem

LeetCode 424. You are given a string s and an...

22 Sep 2022

Find All Anagrams In A String Problem

LeetCode 438. Given two strings s and p, return an...

21 Sep 2022

Sliding Window Maximum Problem

LeetCode 239. You are given an array of integersnums, there...

18 Sep 2022

Minimum Size Subarray Sum Problem

LeetCode 209. Given an array of positive integers nums and...

15 Sep 2022

Longest Substring With At Least K Repeating Characters Problem

LeetCode 395. Given a string s and an integer k,...

10 Apr 2022

Contains Duplicate III Problem

LeetCode 220. Given an integer array nums and two integers...

10 Apr 2022

Contains Duplicate II Problem

LeetCode 219. Given an integer array nums and an integer...

10 Apr 2022

Repeated DNA Sequences Problem

LeetCode 187. The DNA sequence is composed of a series...

04 Dec 2021

Substring with Concatenation of All Words Problem

LeetCode 30. You are given a string s and an...

06 Nov 2021

Longest Continuous Subarray With Absolute Diff Less Than Or Equal To Limit Problem

LeetCode 1438. Given an array of integers nums and an...

02 Dec 2020

Tag Sort

Merge Intervals Problem

LeetCode 56. Given an array of intervals, merge all overlapping...

02 Dec 2020

Number of Islands Problem

LeetCode 200. Given an m x n 2d grid map...

02 Dec 2020

Tag Type Conversion

Implicit Type Conversions in C++

C++ transforms the operands to a common type before performing...

03 Dec 2020

Explicit Type Conversions in C++

An explicit conversion is also called as a cast. There...

03 Dec 2020

Tag Cast

Explicit Type Conversions in C++

An explicit conversion is also called as a cast. There...

03 Dec 2020

Tag Template Specialization

Template Specializations in C++

A template specialization is a separate definition in which the...

03 Dec 2020

Tag Partial Specialization

Template Specializations in C++

A template specialization is a separate definition in which the...

03 Dec 2020

Tag Concurrency

Concurrency II: Introduction Cont'd

Another important question is how threads interact when they access...

04 Dec 2020

Concurrency I: Introduction

A thread is an abstraction for a single running process....

04 Dec 2020

Tag Thread

Concurrency II: Introduction Cont'd

Another important question is how threads interact when they access...

04 Dec 2020

Concurrency I: Introduction

A thread is an abstraction for a single running process....

04 Dec 2020

Tag C++ Concepts

C++ Concept List

A growing list of posts under the topic of C++...

05 Dec 2020

Tag Object Oriented Design

Object Oriented Design Topic List

A growing list of posts under the topic of Object...

05 Dec 2020

Tag Operating System

Operating System Topic List

A growing list of posts under the topic of Operating...

05 Dec 2020

Tag Lambda Expression

Lambda Expressions in C++

A lambda expression is a convenient way of defining an...

07 Dec 2020

Tag Reference

Value Categories in C++

Every C++ expression has a type and belongs to a...

07 Dec 2020

Rvalue References in C++: Perfect Forwarding

Perfect forwarding reduces the need for overloaded functions and helps...

07 Dec 2020

Rvalue References in C++: Move Semantics

The rvalue references enable us to distinguish an lvalue from...

07 Dec 2020

References in C++

A reference is an alias of another object. It stores...

07 Dec 2020

Lvalue References in C++

An lvalue reference is another name of an object. An...

07 Dec 2020

Tag Lvalue Reference

Value Categories in C++

Every C++ expression has a type and belongs to a...

07 Dec 2020

Rvalue References in C++: Perfect Forwarding

Perfect forwarding reduces the need for overloaded functions and helps...

07 Dec 2020

Rvalue References in C++: Move Semantics

The rvalue references enable us to distinguish an lvalue from...

07 Dec 2020

References in C++

A reference is an alias of another object. It stores...

07 Dec 2020

Lvalue References in C++

An lvalue reference is another name of an object. An...

07 Dec 2020

Tag Rvalue Reference

Value Categories in C++

Every C++ expression has a type and belongs to a...

07 Dec 2020

Rvalue References in C++: Perfect Forwarding

Perfect forwarding reduces the need for overloaded functions and helps...

07 Dec 2020

Rvalue References in C++: Move Semantics

The rvalue references enable us to distinguish an lvalue from...

07 Dec 2020

References in C++

A reference is an alias of another object. It stores...

07 Dec 2020

Lvalue References in C++

An lvalue reference is another name of an object. An...

07 Dec 2020

Tag LeetCode

LeetCode Database Solution List

A list of LeetCode database problems and solutions.

12 Dec 2020

LeetCode Solution List

A growing list of LeetCode problems and solutions.

08 Dec 2020

Tag MySQL

How To Specify Unique Constraint For Multiple Columns In MySQL

How to make multiple columns unique (together) in an existing...

29 Sep 2022

How To Select One Row Per ID With Max Value On A Column

Suppose we have the following REIMBURSEMENT table, find the max...

29 Sep 2022

How To Get The Size Of A Table In MySQL

How to get the size of a table in MySQL...

29 Sep 2022

How To Get The Size Of A Database In MySQL

How to get the size of a database in MySQL...

29 Sep 2022

How To Concatenate Multiple Rows Into One Field In MySQL

How to concatenate multiple rows into one field in MySQL...

29 Sep 2022

How To Change The Data Type Of A Column In MySQL

Given a table EMPLOYEE, change the data type of the...

29 Sep 2022

How To Set A Default Value For A MySQL Datetime Column

How to set a default value for a MySQL Datetime...

27 Sep 2022

How To Output MySQL Query Results In CSV Format

This query writes results into a CSV file on the...

27 Sep 2022

How To Get A List Of User Accounts In MySQL

MySQL stores the user information in its own database.

27 Sep 2022

How To Find Duplicate Values In MySQL

Do a SELECT with a GROUP BY clause.

27 Sep 2022

Users That Actively Request Confirmation Messages Problem

LeetCode 1939. Write an SQL query to find the IDs...

11 Sep 2021

Strong Friendship Problem

LeetCode 1949. Write an SQL query to find all the...

11 Sep 2021

Leetcodify Similar Friends Problem

LeetCode 1919. Write an SQL query to report the similar...

11 Sep 2021

Leetcodify Friends Recommendations Problem

LeetCode 1917. Write an SQL query to recommend friends to...

11 Sep 2021

First and Last Call On the Same Day Problem

LeetCode 1972. Write an SQL query to report the IDs...

11 Sep 2021

Find Cutoff Score for Each School Problem

LeetCode 1988. Write an SQL query to report the minimum...

11 Sep 2021

Employees With Missing Information Problem

LeetCode 1965. Write an SQL query to report the IDs...

11 Sep 2021

Employees Whose Manager Left the Company Problem

LeetCode 1978. Write an SQL query to report the IDs...

11 Sep 2021

Count the Number of Experiments Problem

LeetCode 1990. Write an SQL query to report the number...

11 Sep 2021

Count Salary Categories Problem

LeetCode 1907. Write an SQL query to report the number...

11 Sep 2021

Confirmation Rate Problem

LeetCode 1934. Write an SQL query to find the confirmation...

11 Sep 2021

All the Pairs With the Maximum Number of Common Followers Problem

LeetCode 1951. Write an SQL query to find all the...

11 Sep 2021

The Latest Login in 2020 Problem

LeetCode 1890. Write an SQL query to report the latest...

13 Jun 2021

Suspicious Bank Accounts Problem

LeetCode 1843. Write an SQL query to report the IDs...

13 Jun 2021

Page Recommendations II Problem

LeetCode 1892. Write an SQL query to find all the...

13 Jun 2021

Orders With Maximum Quantity Above Average Problem

LeetCode 1867. Write an SQL query to find the order_id...

13 Jun 2021

Maximum Transaction Each Day Problem

LeetCode 1831. Write an SQL query to report the IDs...

13 Jun 2021

League Statistics Problem

LeetCode 1841. Write an SQL query to report the statistics...

13 Jun 2021

Group Employees of the Same Salary Problem

LeetCode 1875. Write an SQL query to report the IDs...

13 Jun 2021

Find Customers With Positive Revenue this Year Problem

LeetCode 1821. Write an SQL query to report the customers...

13 Jun 2021

Convert Date Format Problem

LeetCode 1853. Write an SQL query to convert each date...

13 Jun 2021

Calculate Special Bonus Problem

LeetCode 1873. Write an SQL query to calculate the bonus...

13 Jun 2021

Rearrange Products Table Problem

LeetCode 1795. Write an SQL query to rearrange the Products...

03 Apr 2021

Find Interview Candidates Problem

LeetCode 1811. Write an SQL query to report the name...

03 Apr 2021

Ad-Free Sessions Problem

LeetCode 1809. Write an SQL query to report all the...

03 Apr 2021

Primary Department For Each Employee Problem

LeetCode 1789. Write an SQL query to report all the...

17 Mar 2021

Grand Slam Titles Problem

LeetCode 1783. Write an SQL query to report the number...

08 Mar 2021

Product's Price For Each Store Problem

LeetCode 1777. Write an SQL query to find the price...

05 Mar 2021

Find The Subtasks That Did Not Execute Problem

LeetCode 1767. Write an SQL query to report the IDs...

05 Mar 2021

Recyclable And Low Fat Products Problem

LeetCode 1757. Write an SQL query to find the ids...

14 Feb 2021

Leetflex Banned Accounts Problem

LeetCode 1747. Write an SQL query to find the account_id...

10 Feb 2021

Find Total Time Spent By Each Employee Problem

LeetCode 1741. Write an SQL query to calculate the total...

31 Jan 2021

The Number Of Employees Which Report To Each Employee Problem

LeetCode 1731. Write an SQL query to report the ids...

24 Jan 2021

Find Followers Count Problem

LeetCode 1729. Write an SQL query that will, for each...

20 Jan 2021

MySQL INNER JOIN Clause

The INNER JOIN keyword selects records that have matching values...

09 Jan 2021

MySQL Aliases

Aliases are nicknames. They give us a shorthand way of...

09 Jan 2021

Count Apples And Oranges Problem

LeetCode 1715. Write an SQL query to count the number...

09 Jan 2021

MySQL OR Operator

The OR operator combines two Boolean expressions and returns true...

07 Jan 2021

MySQL LIMIT Operator

The LIMIT clause is used in the SELECT statement to...

07 Jan 2021

MySQL LIKE Operator

The LIKE operator is used in a WHERE clause to...

07 Jan 2021

MySQL IS NULL Operator

To test whether a value is NULL or not, we...

07 Jan 2021

MySQL IN Clause

The IN operator allows us to determine if a specified...

07 Jan 2021

MySQL BETWEEN Operator

The BETWEEN operator selects values within a given range.

07 Jan 2021

MySQL AND Operator

The AND operator is a logical operator that combines two...

07 Jan 2021

MySQL WHERE Clause

The WHERE clause allows us to choose which rows are...

06 Jan 2021

MySQL DISTINCT Clause

In order to remove duplicate rows, we use the DISTINCT...

06 Jan 2021

Biggest Window Between Visits Problem

LeetCode 1709. Write an SQL query that will, for each...

04 Jan 2021

MySQL ORDER BY Clause

The ORDER BY clause is used to sort the result-set...

02 Jan 2021

MySQL SELECT Statement

The SELECT statement allows us to read data from one...

30 Dec 2020

MySQL Tutorial List

A growing list of MySQL tutorials.

30 Dec 2020

Total Sales Amount By Year Problem

LeetCode 1384. Write an SQL query to report the Total...

29 Dec 2020

Sales By Day Of The Week Problem

LeetCode 1479. Write an SQL query to report how many...

29 Dec 2020

Hopper Company Queries III Problem

LeetCode 1651. Write an SQL query to compute the average_ride_distance...

29 Dec 2020

Get The Second Most Recent Activity Problem

LeetCode 1369. Write an SQL query to show the second...

29 Dec 2020

Find The Quiet Students In All Exams Problem

LeetCode 1412. Write an SQL query to report the students...

29 Dec 2020

Tournament Winners Problem

LeetCode 1194. Write an SQL query to find the winner...

28 Dec 2020

Students Report By Geography Problem

LeetCode 618. A U.S graduate school has students from Asia,...

28 Dec 2020

Report Contiguous Dates Problem

LeetCode 1225. Write an SQL query to generate a report...

28 Dec 2020

Median Employee Salary Problem

LeetCode 569. Write a SQL query to find the median...

28 Dec 2020

Market Analysis II Problem

LeetCode 1159. Write an SQL query to find for each...

28 Dec 2020

Hopper Company Queries I Problem

LeetCode 1635. Write an SQL query to report the following...

28 Dec 2020

Game Play Analysis V Problem

LeetCode 1097. Write an SQL query that reports for each...

28 Dec 2020

User Purchase Platform Problem

LeetCode 1127. Write an SQL query to find the total...

27 Dec 2020

Trips And Users Problem

LeetCode 262. Write a SQL query to find the cancellation...

27 Dec 2020

Number Of Transactions Per Visit Problem

LeetCode 1336. Write an SQL query to find how many...

27 Dec 2020

Human Traffic Of Stadium Problem

LeetCode 601. Write an SQL query to display the records...

27 Dec 2020

Hopper Company Queries II Problem

LeetCode 1645. Write an SQL query to report the percentage...

27 Dec 2020

Find Median Given Frequency Of Numbers Problem

LeetCode 571. Write a query to find the median of...

27 Dec 2020

Find Cumulative Salary Of An Employee Problem

LeetCode 579. Write a SQL to get the cumulative sum...

27 Dec 2020

Department Top Three Salaries Problem

LeetCode 185. Write a SQL query to find employees who...

27 Dec 2020

Average Salary: Departments VS Company Problem

LeetCode 615. Given two tables as below, write a query...

27 Dec 2020

Unpopular Books Problem

LeetCode 1098. Write an SQL query that reports the books...

26 Dec 2020

Second Degree Follower Problem

LeetCode 614. Please write a sql query to get the...

26 Dec 2020

Reported Posts II Problem

LeetCode 1132. Write an SQL query to find the average...

26 Dec 2020

Number Of Calls Between Two Persons Problem

LeetCode 1699. Write an SQL query to report the number...

26 Dec 2020

Nth Highest Salary Problem

LeetCode 177. Write a SQL query to get the nth...

26 Dec 2020

New Users Daily Count Problem

LeetCode 1107. Write an SQL query that reports for every...

26 Dec 2020

Monthly Transactions II Problem

LeetCode 1205. Write an SQL query to find for each...

26 Dec 2020

Get Highest Answer Rate Question Problem

LeetCode 578. Write a sql query to identify the question...

26 Dec 2020

Department Highest Salary Problem

LeetCode 184. Write a SQL query to find employees who...

26 Dec 2020

Article Views II Problem

LeetCode 1149. Write an SQL query to find all the...

26 Dec 2020

Active Users Problem

LeetCode 1454. Write an SQL query to find the id...

26 Dec 2020

Winning Candidate Problem

LeetCode 574. Write a sql to find the name of...

25 Dec 2020

Team Scores In Football Tournament Problem

LeetCode 1212. Write an SQL query that selects the team_id,...

25 Dec 2020

Rank Scores Problem

LeetCode 178. Write a SQL query to rank scores. If...

25 Dec 2020

Product Sales Analysis III Problem

LeetCode 1070. Write an SQL query that selects the product...

25 Dec 2020

Movie Rating Problem

LeetCode 1341. Write the following SQL query to find the...

25 Dec 2020

Investments In 2016 Problem

LeetCode 585. Write a query to print the sum of...

25 Dec 2020

Immediate Food Delivery II Problem

LeetCode 1174. Write an SQL query to find the percentage...

25 Dec 2020

Friend Requests II: Who Has The Most Friends Problem

LeetCode 602. In social network like Facebook or Twitter, people...

25 Dec 2020

Countries You Can Safely Invest In Problem

LeetCode 1501. Write an SQL query to find the countries...

25 Dec 2020

Count Student Number In Departments Problem

LeetCode 580. A university uses 2 data tables, student and...

25 Dec 2020

Bank Account Summary Problem

LeetCode 1555. Our bank records all transactions in the table...

25 Dec 2020

Tree Node Problem

LeetCode 608. Given a table tree, id is identifier of...

23 Dec 2020

The Most Recent Orders For Each Product Problem

LeetCode 1549. Write an SQL query to find the most...

23 Dec 2020

Shortest Distance In A Plane Problem

LeetCode 612. Write a query to find the shortest distance...

23 Dec 2020

Rectangles Area Problem

LeetCode 1459. Write an SQL query to report of all...

23 Dec 2020

Product Price At A Given Date Problem

LeetCode 1164. Write an SQL query to find the prices...

23 Dec 2020

Page Recommendations Problem

LeetCode 1264. Write an SQL query to recommend pages to...

23 Dec 2020

Monthly Transactions I Problem

LeetCode 1193. Write an SQL query to find for each...

23 Dec 2020

Market Analysis I Problem

LeetCode 1158. Write an SQL query to find for each...

23 Dec 2020

Managers With At Least 5 Direct Reports Problem

LeetCode 570. Given the Employee table, write a SQL query...

23 Dec 2020

Find The Missing IDs Problem

LeetCode 1613. Write an SQL query to find the missing...

23 Dec 2020

Exchange Seats Problem

LeetCode 626. Mary is a teacher in a middle school...

23 Dec 2020

Customers Who Bought All Products Problem

LeetCode 1045. Write an SQL query for a report that...

23 Dec 2020

Active Business Problem

LeetCode 1126. Write an SQL query to find all active...

23 Dec 2020

The Most Recent Three Orders Problem

LeetCode 1532. Write an SQL query to find the most...

22 Dec 2020

Restaurant Growth Problem

LeetCode 1321. You are the restaurant owner and you want...

22 Dec 2020

Project Employees III Problem

LeetCode 1077. Write an SQL query that reports the most...

22 Dec 2020

Number Of Trusted Contacts Of A Customer Problem

LeetCode 1364. Write an SQL query to find the following...

22 Dec 2020

NPV Queries Problem

LeetCode 1421. Write an SQL query to find the npv...

22 Dec 2020

Last Person To Fit In The Elevator Problem

LeetCode 1204. Write an SQL query to find the person_name...

22 Dec 2020

Highest Grade For Each Student Problem

LeetCode 1112. Write a SQL query to find the highest...

22 Dec 2020

Evaluate Boolean Expression Problem

LeetCode 1440. Write an SQL query to evaluate the boolean...

22 Dec 2020

Calculate Salaries Problem

LeetCode 1468. Write an SQL query to find the salaries...

22 Dec 2020

Activity Participants Problem

LeetCode 1355. Write an SQL query to find the names...

22 Dec 2020

User Activity For The Past 30 Days II Problem

LeetCode 1142. Write an SQL query to find the average...

21 Dec 2020

The Most Frequently Ordered Products For Each Customer Problem

LeetCode 1596. Write an SQL query to find the most...

21 Dec 2020

Running Total For Different Genders Problem

LeetCode 1308. Write an SQL query to find the total...

21 Dec 2020

Friendly Movies Streamed Last Month Problem

LeetCode 1495. Write an SQL query to report the distinct...

21 Dec 2020

Friend Requests I: Overall Acceptance Rate Problem

LeetCode 597. Write an SQL query to find the overall...

21 Dec 2020

Find The Start And End Number Of Continuous Ranges Problem

LeetCode 1285. Write an SQL query to find the start...

21 Dec 2020

Customers Who Bought Products A And B But Not C Problem

LeetCode 1398. Write an SQL query to report the customer_id...

21 Dec 2020

Classes More Than 5 Students Problem

LeetCode 596. Please list out all classes which have more...

21 Dec 2020

Capital Gain/Loss Problem

LeetCode 1393. Write an SQL query to report the Capital...

21 Dec 2020

Biggest Single Number Problem

LeetCode 619. Table my_numbers contains many numbers in column num...

21 Dec 2020

Apples & Oranges Problem

LeetCode 1445. Write an SQL query to report the difference...

21 Dec 2020

All People Report To The Given Manager Problem

LeetCode 1270. Write an SQL query to find employee_id of...

21 Dec 2020

Weather Type In Each Country Problem

LeetCode 1294. Write an SQL query to find the type...

20 Dec 2020

User Activity For The Past 30 Days I Problem

LeetCode 1141. Write an SQL query to find the daily...

20 Dec 2020

Triangle Judgement Problem

LeetCode 610. A pupil Tim gets homework to identify whether...

20 Dec 2020

Students And Examinations Problem

LeetCode 1280. Write an SQL query to find the number...

20 Dec 2020

Sales Person Problem

LeetCode 607. Given three tables, salesperson, company, orders.

20 Dec 2020

Sales Analysis III Problem

LeetCode 1084. Write an SQL query that reports the products...

20 Dec 2020

Sales Analysis II Problem

LeetCode 1083. Write an SQL query that reports the buyers...

20 Dec 2020

Reported Posts Problem

LeetCode 1113. Write an SQL query that reports the number...

20 Dec 2020

Queries Quality And Percentage Problem

LeetCode 1211. Write an SQL query to find each query_name,...

20 Dec 2020

Project Employees II Problem

LeetCode 1076. Write an SQL query that reports all the...

20 Dec 2020

Project Employees I Problem

LeetCode 1075. Write an SQL query that reports the average...

20 Dec 2020

Number Of Comments Per Post Problem

LeetCode 1241. Write an SQL query to find number of...

20 Dec 2020

Not Boring Movies Problem

LeetCode 620. X city opened a new cinema, many people...

20 Dec 2020

Fix Product Name Format Problem

LeetCode 1543. Write an SQL query to report product_name in...

20 Dec 2020

Consecutive Available Seats Problem

LeetCode 603. Several friends at a cinema ticket office would...

20 Dec 2020

Ads Performance Problem

LeetCode 1322. A company is running Ads and wants to...

20 Dec 2020

Top Travellers Problem

LeetCode 1407. Write an SQL query to report the distance...

19 Dec 2020

Swap Salary Problem

LeetCode 627. Given a table salary, such as the one...

19 Dec 2020

Shortest Distance Problem

LeetCode 613. Write a query to find the shortest distance...

19 Dec 2020

Sales Analysis I Problem

LeetCode 1082. Write an SQL query that reports the best...

19 Dec 2020

Reformat Department Table Problem

LeetCode 1179. Write an SQL query to reformat the table...

19 Dec 2020

Product Sales Analysis II Problem

LeetCode 1069. Write an SQL query that reports the total...

19 Dec 2020

Product Sales Analysis I Problem

LeetCode 1068. Write an SQL query that reports all product...

19 Dec 2020

List The Products Ordered In A Period Problem

LeetCode 1327. Write an SQL query to get the names...

19 Dec 2020

Immediate Food Delivery I Problem

LeetCode 1173. Write an SQL query to find the percentage...

19 Dec 2020

Find Users With Valid Emails Problem

LeetCode 1517. Write an SQL query to find the users...

19 Dec 2020

Find Customer Referee Problem

LeetCode 584. Given a table customer holding customers information and...

19 Dec 2020

Customer Placing The Largest Number Of Orders Problem

LeetCode 586. Query the customer_number from the orders table for...

19 Dec 2020

Customer Order Frequency Problem

LeetCode 1511. Write an SQL query to report the customer_id...

19 Dec 2020

Create A Session Bar Chart Problem

LeetCode 1435. You want to know how long a user...

19 Dec 2020

Big Countries Problem

LeetCode 595. Write a SQL solution to output big countries’...

19 Dec 2020

Average Selling Price Problem

LeetCode 1251. Write an SQL query to find the average...

19 Dec 2020

Article Views I Problem

LeetCode 1148. Write an SQL query to find all the...

19 Dec 2020

Actors And Directors Who Cooperated At Least Three Times Problem

LeetCode 1050. Write a SQL query for a report that...

19 Dec 2020

Unique Orders And Customers Per Month Problem

LeetCode 1565. Write an SQL query to find the number...

18 Dec 2020

Sellers With No Sales Problem

LeetCode 1607. Write an SQL query to report the names...

18 Dec 2020

Rising Temperature Problem

LeetCode 197. Write an SQL query to find all dates’...

18 Dec 2020

Game Play Analysis IV Problem

LeetCode 550. Write an SQL query that reports the fraction...

18 Dec 2020

Game Play Analysis III Problem

LeetCode 534. Write an SQL query that reports for each...

18 Dec 2020

Game Play Analysis II Problem

LeetCode 512. Write a SQL query that reports the device...

18 Dec 2020

Game Play Analysis I Problem

LeetCode 511. Write an SQL query that reports the first...

18 Dec 2020

Employee Bonus Problem

LeetCode 577. Select all employee’s name and bonus whose bonus...

18 Dec 2020

Delete Duplicate Emails Problem

LeetCode 196. Write a SQL query to delete all duplicate...

18 Dec 2020

Daily Leads And Partners Problem

LeetCode 1693. Write an SQL query that will, for each...

18 Dec 2020

Customer Who Visited But Did Not Make Any Transactions Problem

LeetCode 1581. Write an SQL query to find the IDs...

18 Dec 2020

Product's Worth Over Invoices Problem

LeetCode 1677. Write an SQL query that will, for all...

17 Dec 2020

Percentage Of Users Attended A Contest Problem

LeetCode 1633. Write an SQL query to find the percentage...

17 Dec 2020

Fix Names In A Table Problem

LeetCode 1667. Write an SQL query to fix the names...

17 Dec 2020

Duplicate Emails Problem

LeetCode 182. Write a SQL query to find all duplicate...

17 Dec 2020

Customers Who Never Order Problem

LeetCode 183. Write a SQL query to find all customers...

17 Dec 2020

Consecutive Numbers Problem

LeetCode 180. Write an SQL query to find all numbers...

17 Dec 2020

Average Time Of Process Per Machine Problem

LeetCode 1661. There is a factory website that has several...

17 Dec 2020

Second Highest Salary Problem

LeetCode 176. Given the Employee table, write a SQL query...

16 Dec 2020

Employees Earning More Than Their Managers Problem

LeetCode 181. Given the Employee table, write a SQL query...

16 Dec 2020

Bank Account Summary II Problem

LeetCode 1587. Write an SQL query to report the name...

16 Dec 2020

Group Sold Products By The Date Problem

LeetCode 1484. Write an SQL query to find for each...

15 Dec 2020

All Valid Triplets That Can Represent A Country Problem

LeetCode 1623. Write an SQL query to find all the...

15 Dec 2020

Warehouse Manager Problem

LeetCode 1571. Write an SQL query to report how much...

13 Dec 2020

Students With Invalid Departments Problem

LeetCode 1350. Write an SQL query to find the id...

13 Dec 2020

Replace Employee ID With The Unique Identifier Problem

LeetCode 1378. Write an SQL query to show the unique...

13 Dec 2020

Patients With A Condition Problem

LeetCode 1527. Write an SQL query to report the patient_id,...

13 Dec 2020

Invalid Tweets Problem

LeetCode 1683. Write an SQL query to find the IDs...

13 Dec 2020

Find The Team Size Problem

LeetCode 1303. Write an SQL query to find the team...

13 Dec 2020

Combine Two Tables Problem

LeetCode 175. Write a SQL query for a report that...

13 Dec 2020

Tag Database

How To Specify Unique Constraint For Multiple Columns In MySQL

How to make multiple columns unique (together) in an existing...

29 Sep 2022

How To Select One Row Per ID With Max Value On A Column

Suppose we have the following REIMBURSEMENT table, find the max...

29 Sep 2022

How To Get The Size Of A Table In MySQL

How to get the size of a table in MySQL...

29 Sep 2022

How To Get The Size Of A Database In MySQL

How to get the size of a database in MySQL...

29 Sep 2022

How To Concatenate Multiple Rows Into One Field In MySQL

How to concatenate multiple rows into one field in MySQL...

29 Sep 2022

How To Change The Data Type Of A Column In MySQL

Given a table EMPLOYEE, change the data type of the...

29 Sep 2022

How To Set A Default Value For A MySQL Datetime Column

How to set a default value for a MySQL Datetime...

27 Sep 2022

How To Output MySQL Query Results In CSV Format

This query writes results into a CSV file on the...

27 Sep 2022

How To Get A List Of User Accounts In MySQL

MySQL stores the user information in its own database.

27 Sep 2022

How To Find Duplicate Values In MySQL

Do a SELECT with a GROUP BY clause.

27 Sep 2022

MySQL INNER JOIN Clause

The INNER JOIN keyword selects records that have matching values...

09 Jan 2021

MySQL Aliases

Aliases are nicknames. They give us a shorthand way of...

09 Jan 2021

MySQL OR Operator

The OR operator combines two Boolean expressions and returns true...

07 Jan 2021

MySQL LIMIT Operator

The LIMIT clause is used in the SELECT statement to...

07 Jan 2021

MySQL LIKE Operator

The LIKE operator is used in a WHERE clause to...

07 Jan 2021

MySQL IS NULL Operator

To test whether a value is NULL or not, we...

07 Jan 2021

MySQL IN Clause

The IN operator allows us to determine if a specified...

07 Jan 2021

MySQL BETWEEN Operator

The BETWEEN operator selects values within a given range.

07 Jan 2021

MySQL AND Operator

The AND operator is a logical operator that combines two...

07 Jan 2021

MySQL WHERE Clause

The WHERE clause allows us to choose which rows are...

06 Jan 2021

MySQL DISTINCT Clause

In order to remove duplicate rows, we use the DISTINCT...

06 Jan 2021

MySQL ORDER BY Clause

The ORDER BY clause is used to sort the result-set...

02 Jan 2021

MySQL SELECT Statement

The SELECT statement allows us to read data from one...

30 Dec 2020

MySQL Tutorial List

A growing list of MySQL tutorials.

30 Dec 2020

Tag Query

How To Specify Unique Constraint For Multiple Columns In MySQL

How to make multiple columns unique (together) in an existing...

29 Sep 2022

How To Select One Row Per ID With Max Value On A Column

Suppose we have the following REIMBURSEMENT table, find the max...

29 Sep 2022

How To Get The Size Of A Table In MySQL

How to get the size of a table in MySQL...

29 Sep 2022

How To Get The Size Of A Database In MySQL

How to get the size of a database in MySQL...

29 Sep 2022

How To Concatenate Multiple Rows Into One Field In MySQL

How to concatenate multiple rows into one field in MySQL...

29 Sep 2022

How To Change The Data Type Of A Column In MySQL

Given a table EMPLOYEE, change the data type of the...

29 Sep 2022

How To Set A Default Value For A MySQL Datetime Column

How to set a default value for a MySQL Datetime...

27 Sep 2022

How To Output MySQL Query Results In CSV Format

This query writes results into a CSV file on the...

27 Sep 2022

How To Get A List Of User Accounts In MySQL

MySQL stores the user information in its own database.

27 Sep 2022

How To Find Duplicate Values In MySQL

Do a SELECT with a GROUP BY clause.

27 Sep 2022

MySQL INNER JOIN Clause

The INNER JOIN keyword selects records that have matching values...

09 Jan 2021

MySQL Aliases

Aliases are nicknames. They give us a shorthand way of...

09 Jan 2021

MySQL OR Operator

The OR operator combines two Boolean expressions and returns true...

07 Jan 2021

MySQL LIMIT Operator

The LIMIT clause is used in the SELECT statement to...

07 Jan 2021

MySQL LIKE Operator

The LIKE operator is used in a WHERE clause to...

07 Jan 2021

MySQL IS NULL Operator

To test whether a value is NULL or not, we...

07 Jan 2021

MySQL IN Clause

The IN operator allows us to determine if a specified...

07 Jan 2021

MySQL BETWEEN Operator

The BETWEEN operator selects values within a given range.

07 Jan 2021

MySQL AND Operator

The AND operator is a logical operator that combines two...

07 Jan 2021

MySQL WHERE Clause

The WHERE clause allows us to choose which rows are...

06 Jan 2021

MySQL DISTINCT Clause

In order to remove duplicate rows, we use the DISTINCT...

06 Jan 2021

MySQL ORDER BY Clause

The ORDER BY clause is used to sort the result-set...

02 Jan 2021

MySQL SELECT Statement

The SELECT statement allows us to read data from one...

30 Dec 2020

Tag String

Word Subsets Problem

LeetCode 916. You are given two string arrays words1 and...

01 Oct 2022

Vowel Spellchecker Problem

LeetCode 966. Given a wordlist, we want to implement a...

01 Oct 2022

Verifying An Alien Dictionary Problem

LeetCode 953. In an alien language, surprisingly, they also use...

01 Oct 2022

Unique Morse Code Words Problem

LeetCode 804. International Morse Code defines a standard encoding where...

01 Oct 2022

Unique Email Addresses Problem

LeetCode 929. Every valid email consists of a local name...

01 Oct 2022

Uncommon Words From Two Sentences Problem

LeetCode 884. A sentence is a string of single-space separated...

01 Oct 2022

Time Based Key-Value Store Problem

LeetCode 981. Design a time-based key-value data structure that can...

01 Oct 2022

Subdomain Visit Count Problem

LeetCode 811. A website domain “discuss.leetcode.com” consists of various subdomains....

01 Oct 2022

String Without Aaa Or Bbb Problem

LeetCode 984. Given two integers a and b, return any...

01 Oct 2022

Stamping The Sequence Problem

LeetCode 936. You are given two strings stamp and target....

01 Oct 2022

Split Array Into Fibonacci Sequence Problem

LeetCode 842. You are given a string of digits num,...

01 Oct 2022

Smallest String Starting From Leaf Problem

LeetCode 988. You are given the root of a binary...

01 Oct 2022

Similar String Groups Problem

LeetCode 839. Two strings Xand Yare similar if we can...

01 Oct 2022

Shortest Distance To A Character Problem

LeetCode 821. Given a string s and a character c...

01 Oct 2022

Short Encoding Of Words Problem

LeetCode 820. A valid encoding of an array of words...

01 Oct 2022

Shifting Letters Problem

LeetCode 848. You are given a string s of lowercase...

01 Oct 2022

Score Of Parentheses Problem

LeetCode 856. Given a balanced parentheses string s, return the...

01 Oct 2022

Satisfiability Of Equality Equations Problem

LeetCode 990. You are given an array of strings equations...

01 Oct 2022

Reverse Only Letters Problem

LeetCode 917. Given a string s, reverse the string according...

01 Oct 2022

Reorder Data In Log Files Problem

LeetCode 937. You are given an array of logs. Each...

01 Oct 2022

Push Dominoes Problem

LeetCode 838. There are n dominoes in a line, and...

01 Oct 2022

Positions Of Large Groups Problem

LeetCode 830. In a string sof lowercase letters, these letters...

01 Oct 2022

Orderly Queue Problem

LeetCode 899. You are given a string s and an...

01 Oct 2022

Numbers At Most N Given Digit Set Problem

LeetCode 902. Given an array of digits which is sorted...

01 Oct 2022

Number Of Lines To Write String Problem

LeetCode 806. You are given a string s of lowercase...

01 Oct 2022

Most Common Word Problem

LeetCode 819. Given a string paragraph and a string array...

01 Oct 2022

Minimum Add To Make Parentheses Valid Problem

LeetCode 921. A parentheses string is valid if and only...

01 Oct 2022

Masking Personal Information Problem

LeetCode 831. You are given a personal information string s,...

01 Oct 2022

Long Pressed Name Problem

LeetCode 925. Your friend is typing his name into a...

01 Oct 2022

Largest Time For Given Digits Problem

LeetCode 949. Given an arrayarr of 4 digits, find the...

01 Oct 2022

K-Similar Strings Problem

LeetCode 854. Strings s1 and s2 are k-similar (for some...

01 Oct 2022

Guess The Word Problem

LeetCode 843. This is an interactive problem.

01 Oct 2022

Groups Of Special-Equivalent Strings Problem

LeetCode 893. You are given an array of strings of...

01 Oct 2022

Goat Latin Problem

LeetCode 824. You are given a string sentence that consist...

01 Oct 2022

Flip String To Monotone Increasing Problem

LeetCode 926. A binary string is monotone increasing if it...

01 Oct 2022

Find The Shortest Superstring Problem

LeetCode 943. Given an array of strings words, return the...

01 Oct 2022

Find And Replace Pattern Problem

LeetCode 890. Given a list of strings words and a...

01 Oct 2022

Find And Replace In String Problem

LeetCode 833. You are given a 0-indexed string s that...

01 Oct 2022

Expressive Words Problem

LeetCode 809. Sometimes people repeat letters to represent extra feeling....

01 Oct 2022

Equal Rational Numbers Problem

LeetCode 972. Given two strings s and t, each of...

01 Oct 2022

Distinct Subsequences II Problem

LeetCode 940. Given a string s, return the number of...

01 Oct 2022

DI String Match Problem

LeetCode 942. A permutation perm of n + 1 integers...

01 Oct 2022

Delete Columns To Make Sorted Problem

LeetCode 944. You are given an array of n strings...

01 Oct 2022

Delete Columns To Make Sorted III Problem

LeetCode 960. You are given an array of n strings...

01 Oct 2022

Delete Columns To Make Sorted II Problem

LeetCode 955. You are given an array of n strings...

01 Oct 2022

Decoded String At Index Problem

LeetCode 880. You are given an encoded string s. To...

01 Oct 2022

Count Unique Characters Of All Substrings Of A Given String Problem

LeetCode 828. Let’s define a function countUniqueChars(s) that returns the...

01 Oct 2022

Buddy Strings Problem

LeetCode 859. Given two strings s and goal, return true...

30 Sep 2022

Backspace String Compare Problem

LeetCode 844. Given two strings s and t, return true...

30 Sep 2022

Ambiguous Coordinates Problem

LeetCode 816. We had some 2-dimensional coordinates, like “(1, 3)”...

30 Sep 2022

Valid Tic-Tac-Toe State Problem

LeetCode 794. Given a Tic-Tac-Toe board as a string array...

28 Sep 2022

Valid Parenthesis String Problem

LeetCode 678. Given a string s containing only three types...

28 Sep 2022

Valid Palindrome II Problem

LeetCode 680. Given a string s, return true if the...

28 Sep 2022

Top K Frequent Words Problem

LeetCode 692. Given an array of strings words and an...

28 Sep 2022

Swap Adjacent In LR String Problem

LeetCode 777. In a string composed of ‘L’, ‘R’, and...

28 Sep 2022

Strange Printer Problem

LeetCode 664. There is a strange printer with the following...

28 Sep 2022

Stickers To Spell Word Problem

LeetCode 691. We are given n different types of stickers....

28 Sep 2022

Special Binary String Problem

LeetCode 761. Special binary strings are binary strings with the...

28 Sep 2022

Solve The Equation Problem

LeetCode 640. Solve a given equation and return the value...

28 Sep 2022

Robot Return To Origin Problem

LeetCode 657. There is a robot starting at the position...

28 Sep 2022

Reorganize String Problem

LeetCode 767. Given a string s, rearrange the characters of...

28 Sep 2022

Partition Labels Problem

LeetCode 763. You are given a string s. We want...

28 Sep 2022

Parse Lisp Expression Problem

LeetCode 736. You are given a string expression representing a...

28 Sep 2022

Open The Lock Problem

LeetCode 752. You have a lock in front of you...

28 Sep 2022

Dota2 Senate Problem

LeetCode 649. In the world of Dota2, there are two...

28 Sep 2022

To Lower Case Problem

LeetCode 709. Given a string s, return the string after...

27 Sep 2022

Shortest Completing Word Problem

LeetCode 748. Given a string licensePlate and an array of...

27 Sep 2022

Rotate String Problem

LeetCode 796. Given two strings s and goal, return true...

27 Sep 2022

Repeated String Match Problem

LeetCode 686. Given two string s a and b, return...

27 Sep 2022

Remove Comments Problem

LeetCode 722. Given a C++ program, remove comments from it....

27 Sep 2022

Prefix And Suffix Search Problem

LeetCode 745. Design a special dictionary with some words that...

27 Sep 2022

Number Of Matching Subsequences Problem

LeetCode 792. Given a string s and an array of...

27 Sep 2022

Number Of Atoms Problem

LeetCode 726. Given a string formula representing a chemical formula,return...

27 Sep 2022

Minimum Ascii Delete Sum For Two Strings Problem

LeetCode 712. Given two strings s1 ands2, return the lowest...

27 Sep 2022

Letter Case Permutation Problem

LeetCode 784. Given a string s, we can transform every...

27 Sep 2022

Find Duplicate File In System Problem

LeetCode 609. Given a list paths of directory info, including...

27 Sep 2022

Palindromic Substrings Problem

LeetCode 647. Given a string s, return the number of...

26 Sep 2022

Map Sum Pairs Problem

LeetCode 677. Design a map that allows you to do...

26 Sep 2022

Implement Magic Dictionary Problem

LeetCode 676. Design a data structure that is initialized with...

26 Sep 2022

Decode Ways II Problem

LeetCode 639. A message containing letters from A-Z can be...

26 Sep 2022

Custom Sort String Problem

LeetCode 791. You are given two strings order and s....

26 Sep 2022

Count Different Palindromic Subsequences Problem

LeetCode 730. Given a string s, return the number of...

26 Sep 2022

Count Binary Substrings Problem

LeetCode 696. Give a binary string s, return the number...

26 Sep 2022

Construct String From Binary Tree Problem

LeetCode 606. Given the root of a binary tree, construct...

26 Sep 2022

Basic Calculator IV Problem

LeetCode 770. Given an expression such as expression = “e...

26 Sep 2022

Accounts Merge Problem

LeetCode 721. Given a list of accounts where each element...

26 Sep 2022

Zuma Game Problem

LeetCode 488. You are playing a variation of the game...

25 Sep 2022

Validate IP Address Problem

LeetCode 468. Given a string queryIP, return “IPv4” if IP...

25 Sep 2022

Unique Substrings In Wraparound String Problem

LeetCode 467. We define the string s to be the...

25 Sep 2022

Tag Validator Problem

LeetCode 591. Given a string representing a code snippet, implement...

25 Sep 2022

Strong Password Checker Problem

LeetCode 420. A password is considered strong if the below...

25 Sep 2022

Freedom Trail Problem

LeetCode 514. In the video game Fallout 4, the quest...

25 Sep 2022

Find The Closest Palindrome Problem

LeetCode 564. Given a string n representing an integer, return...

25 Sep 2022

Student Attendance Record I Problem

LeetCode 551. You are given a string s representing an...

24 Sep 2022

String Compression Problem

LeetCode 443. Given an array of characters chars, compress it...

24 Sep 2022

Sort Characters By Frequency Problem

LeetCode 451. Given a string s, sort it in decreasing...

24 Sep 2022

Serialize And Deserialize BST Problem

LeetCode 449. Serialization is converting a data structure or object...

24 Sep 2022

Reverse Words In A String III Problem

LeetCode 557. Given a string s, reverse the order of...

24 Sep 2022

Reverse String II Problem

LeetCode 541. Given a string s and an integer k,...

24 Sep 2022

Repeated Substring Pattern Problem

LeetCode 459. Given a string s, check if it can...

24 Sep 2022

Remove K Digits Problem

LeetCode 402. Given string num representing a non-negative integer num,...

24 Sep 2022

Reconstruct Original Digits From English Problem

LeetCode 423. Given a string s containing an out-of-order English...

24 Sep 2022

Permutation In String Problem

LeetCode 567. Given two strings s1 and s2, return true...

24 Sep 2022

Ones And Zeroes Problem

LeetCode 474. You are given an array of binary strings...

23 Sep 2022

Number Of Segments In A String Problem

LeetCode 434. You are given a string s, return the...

23 Sep 2022

Next Greater Element III Problem

LeetCode 556. Given a positive integer n, find the smallest...

23 Sep 2022

Minimum Time Difference Problem

LeetCode 539. Given a list of 24-hour clock time points...

23 Sep 2022

Minimum Genetic Mutation Problem

LeetCode 433. A gene string can be represented by an...

23 Sep 2022

Minimum Index Sum Of Two Lists Problem

LeetCode 599. Suppose Andy and Doris want to choose a...

22 Sep 2022

Magical String Problem

LeetCode 481. A magical string s consists of only ‘1’...

22 Sep 2022

Longest Word In Dictionary Through Deleting Problem

LeetCode 524. Given a string s and a string array...

22 Sep 2022

Longest Uncommon Subsequence II Problem

LeetCode 522. Given an array of strings strs, return the...

22 Sep 2022

Longest Uncommon Subsequence I Problem

LeetCode 521. Given two strings a and b, return the...

22 Sep 2022

Longest Repeating Character Replacement Problem

LeetCode 424. You are given a string s and an...

22 Sep 2022

Longest Palindromic Subsequence Problem

LeetCode 516. Given a string s, find the longest palindromic...

22 Sep 2022

Longest Palindrome Problem

LeetCode 409. Given a string s which consists of lowercase...

22 Sep 2022

License Key Formatting Problem

LeetCode 482. You are given a license key represented as...

22 Sep 2022

Keyboard Row Problem

LeetCode 500. Given an array of strings words, return the...

22 Sep 2022

Fraction Addition And Subtraction Problem

LeetCode 592. Given a string expression representing an expression of...

21 Sep 2022

Find All Anagrams In A String Problem

LeetCode 438. Given two strings s and p, return an...

21 Sep 2022

Encode And Decode TinyURL Problem

LeetCode 535. TinyURL is a URL shortening service where you...

21 Sep 2022

Detect Capital Problem

LeetCode 520. We define the usage of capitals in a...

21 Sep 2022

Delete Operation For Two Strings Problem

LeetCode 583. Given two strings word1 and word2, return the...

21 Sep 2022

Complex Number Multiplication Problem

LeetCode 537. A complex number can be represented as a...

21 Sep 2022

Fizz Buzz Problem

LeetCode 412. Given an integer n, return a string array...

19 Sep 2022

Add Strings Problem

LeetCode 415. Given two non-negative integers, num1 and num2 represented...

19 Sep 2022

Verify Preorder Serialization Of A Binary Tree Problem

LeetCode 331. One way to serialize a binary tree is...

18 Sep 2022

Valid Anagram Problem

LeetCode 242. Given two strings s and t, return true...

18 Sep 2022

Shortest Palindrome Problem

LeetCode 214. You are given a string s. You can...

18 Sep 2022

Serialize And Deserialize Binary Tree Problem

LeetCode 297. Serialization is the process of converting a data...

18 Sep 2022

Reverse Vowels Of A String Problem

LeetCode 345. Given a string s, reverse only all the...

18 Sep 2022

Reverse String Problem

LeetCode 344. Write a function that reverses a string. The...

18 Sep 2022

Remove Invalid Parentheses Problem

LeetCode 301. Given a string s that contains parentheses and...

18 Sep 2022

Remove Duplicate Letters Problem

LeetCode 316. Given a string s, remove duplicate letters so...

18 Sep 2022

Word Pattern Problem

LeetCode 290. Given a pattern and a string s, find...

16 Sep 2022

Ransom Note Problem

LeetCode 383. Given two stings ransomNote and magazine, return true...

16 Sep 2022

Palindrome Pairs Problem

LeetCode 336. Given a list of unique words, return all...

16 Sep 2022

Mini Parser Problem

LeetCode 385. Given a string s represents the serialization of...

15 Sep 2022

Maximum Product Of Word Lengths Problem

LeetCode 318. Given a string array words, return the maximum...

15 Sep 2022

Longest Substring With At Least K Repeating Characters Problem

LeetCode 395. Given a string s and an integer k,...

10 Apr 2022

Longest Absolute File Path Problem

LeetCode 388. Suppose we have a file system that stores...

10 Apr 2022

Isomorphic Strings Problem

LeetCode 205. Given two strings s and t, determine if...

10 Apr 2022

Is Subsequence Problem

LeetCode 392. Given two strings s and t, return true...

10 Apr 2022

Integer To English Words Problem

LeetCode 273. Convert a non-negative integer num to its English...

10 Apr 2022

First Unique Character In A String Problem

LeetCode 387. Given a string s, find the first non-repeating...

10 Apr 2022

Find The Difference Problem

LeetCode 389. You are given two strings s and t....

10 Apr 2022

Expression Add Operators Problem

LeetCode 282. Given a string num that contains only digits...

10 Apr 2022

Different Ways To Add Parentheses Problem

LeetCode 241. Given a string expression of numbers and operators,...

10 Apr 2022

Design Add And Search Words Data Structure Problem

LeetCode 211. Design a data structure that supports adding new...

10 Apr 2022

Decode String Problem

LeetCode 394. Given an encoded string, return its decoded string....

10 Apr 2022

Bulls And Cows Problem

LeetCode 299. You are playing the Bulls and Cows game...

10 Apr 2022

Binary Tree Paths Problem

LeetCode 257. Given the root of a binary tree, return...

10 Apr 2022

Basic Calculator Problem

LeetCode 224. Given a string s representing a valid expression,...

10 Apr 2022

Basic Calculator II Problem

LeetCode 227. Given a string s which represents an expression,...

10 Apr 2022

Additive Number Problem

LeetCode 306. Additive number is a string whose digits can...

10 Apr 2022

Reverse Words In A String Problem

LeetCode 151. Given an input string s, reverse the order...

04 Dec 2021

Repeated DNA Sequences Problem

LeetCode 187. The DNA sequence is composed of a series...

04 Dec 2021

Largest Number Problem

LeetCode 179. Given a list of non-negative integers nums, arrange...

04 Dec 2021

Fraction To Recurring Decimal Problem

LeetCode 166. Given two integers representing the numerator and denominator...

04 Dec 2021

Excel Sheet Column Title Problem

LeetCode 168. Given an integer columnNumber, return its corresponding column...

04 Dec 2021

Excel Sheet Column Number Problem

LeetCode 171. Given a string columnTitle that represents the column...

04 Dec 2021

Compare Version Numbers Problem

LeetCode 165. Given two version numbers,version1 and version2, compare them....

04 Dec 2021

Word Break Problem

LeetCode 139. Given a string s and a dictionary of...

03 Dec 2021

Word Break II Problem

LeetCode 140. Given a string s and a dictionary of...

03 Dec 2021

Palindrome Partitioning Problem

LeetCode 131. Given a string s, partition s such that...

03 Dec 2021

Palindrome Partitioning II Problem

LeetCode 132. Given a string s, partition s such that...

03 Dec 2021

Word Ladder Problem

LeetCode 127. Given two words, beginWord and endWord, and a...

29 Nov 2021

Word Ladder II Problem

LeetCode 126. Given two words, beginWord and endWord, and a...

29 Nov 2021

Valid Palindrome Problem

LeetCode 125. A phrase is a palindrome if, after converting...

29 Nov 2021

Distinct Subsequences Problem

LeetCode 115. Given two strings s and t, return the...

29 Nov 2021

Interleaving String Problem

LeetCode 97. Given strings s1, s2, and s3, find whether...

16 Nov 2021

Scramble String Problem

LeetCode 87. Given two strings s1 and s2 of the...

14 Nov 2021

Restore IP Addresses Problem

LeetCode 93. Given a string s containing only digits, return...

14 Nov 2021

Decode Ways Problem

LeetCode 91. Given a string s containing only digits, return...

14 Nov 2021

Simplify Path Problem

LeetCode 71. Given a string path, which is an absolute...

10 Nov 2021

Edit Distance Problem

LeetCode 72. Given two strings word1 and word2, return the...

10 Nov 2021

Valid Number Problem

LeetCode 65. Given a string s, return true if s...

09 Nov 2021

Text Justification Problem

LeetCode 68. Given an array of strings words and a...

09 Nov 2021

Valid Number Problem

LeetCode 67. A robot is located at the top-left corner...

09 Nov 2021

Length Of Last Word Problem

LeetCode 58. Given a string s consisting of some words...

08 Nov 2021

Zigzag Conversion Problem

LeetCode 6. Write the code that will take a string...

06 Nov 2021

Wildcard Matching Problem

LeetCode 44. Write the code that will take a string...

06 Nov 2021

Substring with Concatenation of All Words Problem

LeetCode 30. You are given a string s and an...

06 Nov 2021

Regular Expression Matching Problem

LeetCode 10. Given an input string s and a pattern...

06 Nov 2021

Multiply Strings Problem

LeetCode 43. Given two non-negative integers num1 and num2 represented...

06 Nov 2021

Longest Valid Parentheses Problem

LeetCode 32. Given a string containing just the characters ‘(‘...

06 Nov 2021

Integer to Roman Problem

LeetCode 12. Given an integer, convert it to a roman...

06 Nov 2021

Implement strStr() Problem

LeetCode 28. Implement strStr().

06 Nov 2021

Group Anagrams Problem

LeetCode 49. Given an array of strings strs, group the...

06 Nov 2021

Count and Say Problem

LeetCode 38. Write the code that will take a string...

06 Nov 2021

Valid Parentheses Problem

LeetCode 20. Given a string s containing just the characters...

05 Nov 2021

Roman to Integer Problem

LeetCode 13. Given a roman numeral, convert it to an...

05 Nov 2021

Longest Common Prefix Problem

LeetCode 14. Write a function to find the longest common...

05 Nov 2021

Letter Combinations of a Phone Number Problem

LeetCode 17. Given a string containing digits from 2-9 inclusive,...

05 Nov 2021

Generate Parentheses Problem

LeetCode 22. Given n pairs of parentheses, write a function...

05 Nov 2021

Determine Color Of A Chessboard Square Problem

LeetCode 1812. You are given coordinates, a string that represents...

03 Apr 2021

String To Interger (atoi) Problem

LeetCode 8. Implement the myAtoi(string s) function, which converts a...

17 Mar 2021

Tag Reverse

Reverse Prefix of Word Problem

LeetCode 2000. Given a 0-indexed string word and a character...

12 Sep 2021

Tag DFS

Smallest Greater Multiple Made of Two Digits Problem

LeetCode 1999. Given three integers, k, digit1, and digit2, you...

12 Sep 2021

Tag Git Reset

How to Undo a Git Add Before Commit

Short answers to the question how to undo a git...

04 Nov 2021

How to Undo the Most Recent Local Commit in Git

Short answers to the question how to undo the most...

03 Nov 2021

Tag Git Branch

How to Rename a Local Git Branch

Short answers to the question how to rename a local...

04 Nov 2021

How to Delete a Git Branch Locally and Remotely

Short answers to the question how to delete a git...

04 Nov 2021

How to Checkout a Remote Git Branch

Short answers to the question how to checkout a remote...

04 Nov 2021

Tag Git

Git Short Answers List

A growing list of Git questions and short answers.

04 Nov 2021

Tag Two Pointers

Squares Of A Sorted Array Problem

LeetCode 977. Given an integer array nums sorted in non-decreasing...

01 Oct 2022

Sort Array By Parity Problem

LeetCode 905. Given an integer array nums, move all the...

01 Oct 2022

Sort Array By Parity II Problem

LeetCode 922. Given an array of integers nums, half of...

01 Oct 2022

Shortest Distance To A Character Problem

LeetCode 821. Given a string s and a character c...

01 Oct 2022

Reverse Only Letters Problem

LeetCode 917. Given a string s, reverse the string according...

01 Oct 2022

Push Dominoes Problem

LeetCode 838. There are n dominoes in a line, and...

01 Oct 2022

Pancake Sorting Problem

LeetCode 969. Given an array of integers arr, sort the...

01 Oct 2022

Most Profit Assigning Work Problem

LeetCode 826. You have n jobs and m workers. You...

01 Oct 2022

Middle Of The Linked List Problem

LeetCode 876. Given the head of a singly linked list,...

01 Oct 2022

Longest Mountain In Array Problem

LeetCode 845. Given an integer array arr, return the length...

01 Oct 2022

Long Pressed Name Problem

LeetCode 925. Your friend is typing his name into a...

01 Oct 2022

Interval List Intersections Problem

LeetCode 986. You are given two lists of closed intervals,...

01 Oct 2022

Friends Of Appropriate Ages Problem

LeetCode 825. There are n persons on a social media...

01 Oct 2022

Flipping An Image Problem

LeetCode 832. Given an n x n binary matrix image,...

01 Oct 2022

Expressive Words Problem

LeetCode 809. Sometimes people repeat letters to represent extra feeling....

01 Oct 2022

DI String Match Problem

LeetCode 942. A permutation perm of n + 1 integers...

01 Oct 2022

Boats To Save People Problem

LeetCode 881. You are given an array people where people[i]...

30 Sep 2022

Bag Of Tokens Problem

LeetCode 948. You have an initial power of power, an...

30 Sep 2022

Backspace String Compare Problem

LeetCode 844. Given two strings s and t, return true...

30 Sep 2022

Advantage Shuffle Problem

LeetCode 870. You are given two integer arrays nums1 and...

30 Sep 2022

3Sum With Multiplicity Problem

LeetCode 923. Given an integer array arr, and an integer...

30 Sep 2022

Valid Triangle Number Problem

LeetCode 611. Given an integer array nums, return the number...

28 Sep 2022

Valid Palindrome II Problem

LeetCode 680. Given a string s, return true if the...

28 Sep 2022

Swap Adjacent In LR String Problem

LeetCode 777. In a string composed of ‘L’, ‘R’, and...

28 Sep 2022

Partition Labels Problem

LeetCode 763. You are given a string s. We want...

28 Sep 2022

Two Sum IV - Input Is A BST Problem

LeetCode 653. Given the root of a Binary Search Tree...

27 Sep 2022

Sum Of Square Numbers Problem

LeetCode 633. Given a non-negative integer c, decide whether there’re...

27 Sep 2022

Number Of Subarrays With Bounded Maximum Problem

LeetCode 795. Given an integer array nums and two integers...

27 Sep 2022

Find K-Th Smallest Pair Distance Problem

LeetCode 719. The distance of a pair of integers a...

26 Sep 2022

Find K Closest Elements Problem

LeetCode 658. Given a sorted integer array arr, two integers...

26 Sep 2022

Count Binary Substrings Problem

LeetCode 696. Give a binary string s, return the number...

26 Sep 2022

String Compression Problem

LeetCode 443. Given an array of characters chars, compress it...

24 Sep 2022

Shortest Unsorted Continuous Subarray Problem

LeetCode 581. Given an integer array nums, you need to...

24 Sep 2022

Reverse Words In A String III Problem

LeetCode 557. Given a string s, reverse the order of...

24 Sep 2022

Reverse String II Problem

LeetCode 541. Given a string s and an integer k,...

24 Sep 2022

Permutation In String Problem

LeetCode 567. Given two strings s1 and s2, return true...

24 Sep 2022

Next Greater Element III Problem

LeetCode 556. Given a positive integer n, find the smallest...

23 Sep 2022

Magical String Problem

LeetCode 481. A magical string s consists of only ‘1’...

22 Sep 2022

Longest Word In Dictionary Through Deleting Problem

LeetCode 524. Given a string s and a string array...

22 Sep 2022

Longest Uncommon Subsequence II Problem

LeetCode 522. Given an array of strings strs, return the...

22 Sep 2022

K-Diff Pairs In An Array Problem

LeetCode 532. Given an array of integers nums and an...

22 Sep 2022

Heaters Problem

LeetCode 475. Winter is coming! During the contest, your first...

22 Sep 2022

Circular Array Loop Problem

LeetCode 457. You are playing a game involving a circular...

19 Sep 2022

Assign Cookies Problem

LeetCode 455. Assume you are an awesome parent and want...

19 Sep 2022

Reverse Vowels Of A String Problem

LeetCode 345. Given a string s, reverse only all the...

18 Sep 2022

Reverse String Problem

LeetCode 344. Write a function that reverses a string. The...

18 Sep 2022

Move Zeroes Problem

LeetCode 283. Given an integer array nums, move all 0’s...

15 Sep 2022

Is Subsequence Problem

LeetCode 392. Given two strings s and t, return true...

10 Apr 2022

Intersection Of Two Arrays II Problem

LeetCode 350. Given two integer arrays nums1 and nums2, return...

10 Apr 2022

Happy Number Problem

LeetCode 202. Write an algorithm to determine if a number...

10 Apr 2022

Find The Duplicate Number Problem

LeetCode 287. Given an array of integers nums containingn +...

10 Apr 2022

Find Median From Data Stream Problem

LeetCode 295. The median is the middle value in an...

10 Apr 2022

Rotate Array Problem

LeetCode 189. Given an array, rotate the array to the...

04 Dec 2021

Reverse Words In A String Problem

LeetCode 151. Given an input string s, reverse the order...

04 Dec 2021

Intersection Of Two Linked Lists Problem

LeetCode 160. Given the heads of two singly linked-lists headA...

04 Dec 2021

Compare Version Numbers Problem

LeetCode 165. Given two version numbers,version1 and version2, compare them....

04 Dec 2021

Sort List Problem

LeetCode 148. Given the head of a linked list, return...

03 Dec 2021

Reorder List Problem

LeetCode 143. You are given the head of a singly...

03 Dec 2021

Linked List Cycle Problem

LeetCode 141. Given head, the head of a linked list,...

03 Dec 2021

Linked List Cycle II Problem

LeetCode 142. Given the head of a linked list, return...

03 Dec 2021

Valid Palindrome Problem

LeetCode 125. A phrase is a palindrome if, after converting...

29 Nov 2021

Remove Duplicates from Sorted List II Problem

LeetCode 82. Given the head of a sorted linked list,...

14 Nov 2021

Remove Duplicates from Sorted Array II Problem

LeetCode 80. Given an integer array nums sorted in non-decreasing...

14 Nov 2021

Partition List Problem

LeetCode 86. Given the head of a linked list and...

14 Nov 2021

Merge Sorted Array Problem

LeetCode 88. You are given two integer arrays nums1 and...

14 Nov 2021

Sort Colors Problem

LeetCode 75. Given an array nums with n objects colored...

10 Nov 2021

Rotate List Problem

LeetCode 61. Given the head of a linked list, rotate...

09 Nov 2021

Trapping Rain Water Problem

LeetCode 42. Given n non-negative integers representing an elevation map...

06 Nov 2021

Search in Rotated Sorted Array Problem

LeetCode 33. Given the array nums after the possible rotation...

06 Nov 2021

Remove Element Problem

LeetCode 27. Given an integer array nums and an integer...

06 Nov 2021

Next Permutation Problem

LeetCode 31. Implement next permutation, which rearranges numbers into the...

06 Nov 2021

Implement strStr() Problem

LeetCode 28. Implement strStr().

06 Nov 2021

3Sum Closest Problem

LeetCode 16. Given an integer array nums of length n...

06 Nov 2021

Remove Nth Node From End of List Problem

LeetCode 19. Given the head of a linked list, remove...

05 Nov 2021

Remove Duplicates from Sorted Array Problem

LeetCode 26. Given an integer array nums sorted in non-decreasing...

05 Nov 2021

Container With Most Water Problem

LeetCode 11. Given n non-negative integers a_1, a_2, …, a_n...

05 Nov 2021

Tag BST

Depth of BST Given Insertion Order Problem

LeetCode 1902. You are given a 0-indexed integer array order...

05 Nov 2021

Tag Dynamic Programming

Valid Permutations For DI Sequence Problem

LeetCode 903. You are given a string s of length...

01 Oct 2022

Tallest Billboard Problem

LeetCode 956. You are installing a billboard and want it...

01 Oct 2022

Super Egg Drop Problem

LeetCode 887. You are given k identical eggs and you...

01 Oct 2022

Sum Of Subarray Minimums Problem

LeetCode 907. Given an array of integers arr, find the...

01 Oct 2022

Sum Of Distances In Tree Problem

LeetCode 834. There is an undirected connected tree with n...

01 Oct 2022

Stone Game Problem

LeetCode 877. Alice and Bob play a game with piles...

01 Oct 2022

Split Array With Same Average Problem

LeetCode 805. You are given an integer array nums.

01 Oct 2022

Soup Servings Problem

LeetCode 808. There are two types of soup, type A...

01 Oct 2022

Shortest Path Visiting All Nodes Problem

LeetCode 847. You have an undirected, connected graph of n...

01 Oct 2022

Race Car Problem

LeetCode 818. Your car starts at position 0 and speed...

01 Oct 2022

Push Dominoes Problem

LeetCode 838. There are n dominoes in a line, and...

01 Oct 2022

Profitable Schemes Problem

LeetCode 879. There is a group of n members, and...

01 Oct 2022

Odd Even Jump Problem

LeetCode 975. You are given an integer array arr. From...

01 Oct 2022

Numbers At Most N Given Digit Set Problem

LeetCode 902. Given an array of digits which is sorted...

01 Oct 2022

Number Of Squareful Arrays Problem

LeetCode 996. An array is squareful if the sum of...

01 Oct 2022

Number Of Music Playlists Problem

LeetCode 920. Your music player contains n different songs. You...

01 Oct 2022

New 21 Game Problem

LeetCode 837. Alice plays the following game, loosely based on...

01 Oct 2022

Minimum Swaps To Make Sequences Increasing Problem

LeetCode 801. You are given two integer arrays of the...

01 Oct 2022

Minimum Number Of Refueling Stops Problem

LeetCode 871. A car travels from a starting position to...

01 Oct 2022

Minimum Falling Path Sum Problem

LeetCode 931. Given an n x n array of integers...

01 Oct 2022

Minimum Cost To Merge Stones Problem

LeetCode 1000. There are n piles of stones arranged in...

01 Oct 2022

Minimum Cost For Tickets Problem

LeetCode 983. You have planned some train traveling one year...

01 Oct 2022

Maximum Sum Circular Subarray Problem

LeetCode 918. Given a circular integer array nums of length...

01 Oct 2022

Longest Turbulent Subarray Problem

LeetCode 978. Given an integer array arr, return the length...

01 Oct 2022

Longest Mountain In Array Problem

LeetCode 845. Given an integer array arr, return the length...

01 Oct 2022

Length Of Longest Fibonacci Subsequence Problem

LeetCode 873. Given a strictly increasing array arr of positive...

01 Oct 2022

Least Operators To Express Number Problem

LeetCode 964. Given a single positive integer x, we will...

01 Oct 2022

Largest Sum Of Averages Problem

LeetCode 813. You are given an integer array nums and...

01 Oct 2022

Knight Dialer Problem

LeetCode 935. The chess knight has a unique movement, it...

01 Oct 2022

Flip String To Monotone Increasing Problem

LeetCode 926. A binary string is monotone increasing if it...

01 Oct 2022

Find The Shortest Superstring Problem

LeetCode 943. Given an array of strings words, return the...

01 Oct 2022

Distinct Subsequences II Problem

LeetCode 940. Given a string s, return the number of...

01 Oct 2022

Delete Columns To Make Sorted III Problem

LeetCode 960. You are given an array of n strings...

01 Oct 2022

Count Unique Characters Of All Substrings Of A Given String Problem

LeetCode 828. Let’s define a function countUniqueChars(s) that returns the...

01 Oct 2022

Cat And Mouse Problem

LeetCode 913. A game on an undirected graph is played...

30 Sep 2022

Bitwise ORs Of Subarrays Problem

LeetCode 898. We have an array arr of non-negative integers....

30 Sep 2022

Binary Trees With Factors Problem

LeetCode 823. Given an array of unique integers, arr, where...

30 Sep 2022

Binary Tree Cameras Problem

LeetCode 968. You are given the root of a binary...

30 Sep 2022

All Possible Full Binary Trees Problem

LeetCode 894. Given an integer n, return a list of...

30 Sep 2022

Valid Parenthesis String Problem

LeetCode 678. Given a string s containing only three types...

28 Sep 2022

Strange Printer Problem

LeetCode 664. There is a strange printer with the following...

28 Sep 2022

Stickers To Spell Word Problem

LeetCode 691. We are given n different types of stickers....

28 Sep 2022

Shopping Offers Problem

LeetCode 638. In LeetCode Store, there are n items to...

28 Sep 2022

Knight Probability In Chessboard Problem

LeetCode 688. On an n x n chessboard, a knight...

28 Sep 2022

Cherry Pickup Problem

LeetCode 741. You are given an n x n grid...

28 Sep 2022

2 Keys Keyboard Problem

LeetCode 650. There is only one character ‘A’ on the...

28 Sep 2022

Rotated Digits Problem

LeetCode 788. An integer x is a good if after...

27 Sep 2022

Partition To K Equal Sum Subsets Problem

LeetCode 698. Given an integer array nums and an integer...

27 Sep 2022

Number Of Longest Increasing Subsequence Problem

LeetCode 673. Given an integer arraynums, return the number of...

27 Sep 2022

Minimum Ascii Delete Sum For Two Strings Problem

LeetCode 712. Given two strings s1 ands2, return the lowest...

27 Sep 2022

Min Cost Climbing Stairs Problem

LeetCode 746. You are given an integer array cost where...

27 Sep 2022

Maximum Sum Of 3 Non-Overlapping Subarrays Problem

LeetCode 689. Given an integer array nums and an integer...

27 Sep 2022

Maximum Length Of Repeated Subarray Problem

LeetCode 718. Given two integer arrays nums1 and nums2, return...

27 Sep 2022

Maximum Length Of Pair Chain Problem

LeetCode 646. You are given an array of n pairs...

27 Sep 2022

Palindromic Substrings Problem

LeetCode 647. Given a string s, return the number of...

26 Sep 2022

Largest Plus Sign Problem

LeetCode 764. You are given an integer n. You have...

26 Sep 2022

K Inverse Pairs Array Problem

LeetCode 629. For an integer array nums, an inverse pair...

26 Sep 2022

Domino And Tromino Tiling Problem

LeetCode 790. You have two types of tiles, a 2...

26 Sep 2022

Delete And Earn Problem

LeetCode 740. You are given an integer array nums. You...

26 Sep 2022

Decode Ways II Problem

LeetCode 639. A message containing letters from A-Z can be...

26 Sep 2022

Count Different Palindromic Subsequences Problem

LeetCode 730. Given a string s, return the number of...

26 Sep 2022

Cheapest Flights Within K Stops Problem

LeetCode 787. There are n cities connected by some number...

26 Sep 2022

Champagne Tower Problem

LeetCode 799. We stack glasses in a pyramid, where the...

26 Sep 2022

Best Time To Buy And Sell Stock With Transaction Fee Problem

LeetCode 714. You are given an array prices where prices[i]...

26 Sep 2022

Zuma Game Problem

LeetCode 488. You are playing a variation of the game...

25 Sep 2022

Unique Substrings In Wraparound String Problem

LeetCode 467. We define the string s to be the...

25 Sep 2022

Predict The Winner Problem

LeetCode 486. You are given an integer array nums. Two...

25 Sep 2022

Partition Equal Subset Sum Problem

LeetCode 416. Given a non-empty array nums containing only positive...

25 Sep 2022

Non-Negative Integers Without Consecutive Ones Problem

LeetCode 600. Given a positive integer n, return the number...

25 Sep 2022

Frog Jump Problem

LeetCode 403. A frog is crossing a river. The river...

25 Sep 2022

Freedom Trail Problem

LeetCode 514. In the video game Fallout 4, the quest...

25 Sep 2022

Target Sum Problem

LeetCode 494. You are given an integer array nums and...

24 Sep 2022

Student Attendance Record II Problem

LeetCode 552. An attendance record for a student can be...

24 Sep 2022

Split Array Largest Sum Problem

LeetCode 410. Given an array nums which consists of non-negative...

24 Sep 2022

Remove Boxes Problem

LeetCode 546. You are given several boxes with different colors...

24 Sep 2022

Poor Pigs Problem

LeetCode 458. There are buckets buckets of liquid, where exactly...

24 Sep 2022

Out Of Boundary Paths Problem

LeetCode 576. There is an m x n grid with...

23 Sep 2022

Optimal Division Problem

LeetCode 553. You are given an integer array nums. The...

23 Sep 2022

Ones And Zeroes Problem

LeetCode 474. You are given an array of binary strings...

23 Sep 2022

Non-Overlapping Intervals Problem

LeetCode 435. Given an array of intervals intervals where intervals[i]...

23 Sep 2022

Matchsticks To Square Problem

LeetCode 473. You are given an integer array matchsticks where...

22 Sep 2022

Longest Palindromic Subsequence Problem

LeetCode 516. Given a string s, find the longest palindromic...

22 Sep 2022

Fibonacci Number Problem

LeetCode 509. The Fibonacci numbers, commonly denoted F(n) form a...

21 Sep 2022

Delete Operation For Two Strings Problem

LeetCode 583. Given two strings word1 and word2, return the...

21 Sep 2022

Coin Change II Problem

LeetCode 518. You are given an integer array coins representing...

19 Sep 2022

Arithmetic Slices Problem

LeetCode 413. An integer array is called arithmetic if it...

19 Sep 2022

Arithmetic Slices II - Subsequence Problem

LeetCode 446. Given an integer array nums, return the number...

19 Sep 2022

01 Matrix Problem

LeetCode 542. Given an m x n binary matrix mat,...

19 Sep 2022

Wiggle Subsequence Problem

LeetCode 376. A wiggle sequence is a sequence where the...

18 Sep 2022

Ugly Number II Problem

LeetCode 264. An ugly number is a positive integer whose...

18 Sep 2022

Rotate Function Problem

LeetCode 396. You are given an integer array nums of...

18 Sep 2022

Perfect Squares Problem

LeetCode 279. Given an integer n, return the least number...

16 Sep 2022

Number Of Digit One Problem

LeetCode 233. Given an integer n, count the total number...

15 Sep 2022

Maximal Square Problem

LeetCode 221. Given an m x n binary matrix filled...

15 Sep 2022

Longest Increasing Subsequence Problem

LeetCode 300. Given an integer array nums, return the length...

10 Apr 2022

Longest Increasing Path In A Matrix Problem

LeetCode 329. Given an m x n integers matrix, return...

10 Apr 2022

Largest Divisible Subset Problem

LeetCode 368. Given a set of distinct positive integers nums,...

10 Apr 2022

Is Subsequence Problem

LeetCode 392. Given two strings s and t, return true...

10 Apr 2022

Integer Replacement Problem

LeetCode 397. Given a positive integer n,you can apply one...

10 Apr 2022

Integer Break Problem

LeetCode 343. Given an integer n, break it into the...

10 Apr 2022

House Robber III Problem

LeetCode 337. The thief has found himself a new place...

10 Apr 2022

House Robber II Problem

LeetCode 213. You are a professional robber planning to rob...

10 Apr 2022

Guess Number Higher Or Lower II Problem

LeetCode 375. We are playing the Guessing Game. The game...

10 Apr 2022

Different Ways To Add Parentheses Problem

LeetCode 241. Given a string expression of numbers and operators,...

10 Apr 2022

Counting Bits Problem

LeetCode 338. Given an integer n, return an array ans...

10 Apr 2022

Count Numbers With Unique Digits Problem

LeetCode 357. Given an integer n, return the count of...

10 Apr 2022

Combination Sum IV Problem

LeetCode 377. Given an array of distinct integers nums and...

10 Apr 2022

Coin Change Problem

LeetCode 322. You are given an integer array coins representing...

10 Apr 2022

Burst Balloons Problem

LeetCode 312. You are given n balloons, indexed from 0...

10 Apr 2022

Best Time To Buy And Sell Stock With Cooldown Problem

LeetCode 309. You are given an array prices where prices[i]...

10 Apr 2022

Maximum Product Subarray Problem

LeetCode 152. Given an integer array nums, find a contiguous...

04 Dec 2021

House Robber Problem

LeetCode 198. You are a professional robber planning to rob...

04 Dec 2021

Dungeon Game Problem

LeetCode 174. The demons had captured the princess and imprisoned...

04 Dec 2021

Best Time To Buy And Sell Stock IV Problem

LeetCode 188. You are given an integer array prices where...

04 Dec 2021

Word Break Problem

LeetCode 139. Given a string s and a dictionary of...

03 Dec 2021

Word Break II Problem

LeetCode 140. Given a string s and a dictionary of...

03 Dec 2021

Palindrome Partitioning Problem

LeetCode 131. Given a string s, partition s such that...

03 Dec 2021

Palindrome Partitioning II Problem

LeetCode 132. Given a string s, partition s such that...

03 Dec 2021

Triangle Problem

LeetCode 120. Given a triangle array, return the minimum path...

29 Nov 2021

Pascal's Triangle Problem

LeetCode 118. Given an integer numRows, return the first numRows...

29 Nov 2021

Pascal's Triangle II Problem

LeetCode 119. Given an integer rowIndex, return the rowIndex^th (0-indexed)...

29 Nov 2021

Distinct Subsequences Problem

LeetCode 115. Given two strings s and t, return the...

29 Nov 2021

Binary Tree Maximum Path Sum Problem

LeetCode 124. A path in a binary tree is a...

29 Nov 2021

Best Time To Buy And Sell Stock Problem

LeetCode 121. You are given an array prices where prices[i]...

29 Nov 2021

Best Time To Buy And Sell Stock Iii Problem

LeetCode 123. You are given an array prices where prices[i]...

29 Nov 2021

Best Time To Buy And Sell Stock Ii Problem

LeetCode 122. You are given an integer array prices where...

29 Nov 2021

Interleaving String Problem

LeetCode 97. Given strings s1, s2, and s3, find whether...

16 Nov 2021

Unique Binary Search Trees Problem

LeetCode 96. Given an integer n, return the number of...

14 Nov 2021

Unique Binary Search Trees II Problem

LeetCode 95. Given an integer n, return all the structurally...

14 Nov 2021

Scramble String Problem

LeetCode 87. Given two strings s1 and s2 of the...

14 Nov 2021

Maximal Rectangle Problem

LeetCode 85. Given a rows x cols binary matrix filled...

14 Nov 2021

Decode Ways Problem

LeetCode 91. Given a string s containing only digits, return...

14 Nov 2021

Edit Distance Problem

LeetCode 72. Given two strings word1 and word2, return the...

10 Nov 2021

Unique Paths Problem

LeetCode 62. A robot is located at the top-left corner...

09 Nov 2021

Unique Paths II Problem

LeetCode 63. A robot is located at the top-left corner...

09 Nov 2021

Minimum Path Sum Problem

LeetCode 64. Given a m x n grid filled with...

09 Nov 2021

Climbing Stairs Problem

LeetCode 70. You are climbing a staircase. It takes n...

09 Nov 2021

Maximum Subarray Problem

LeetCode 53. Given an integer array nums, find the contiguous...

08 Nov 2021

Jump Game Problem

LeetCode 55. Given an m x n matrix, return all...

08 Nov 2021

Wildcard Matching Problem

LeetCode 44. Write the code that will take a string...

06 Nov 2021

Trapping Rain Water Problem

LeetCode 42. Given n non-negative integers representing an elevation map...

06 Nov 2021

Regular Expression Matching Problem

LeetCode 10. Given an input string s and a pattern...

06 Nov 2021

Longest Valid Parentheses Problem

LeetCode 32. Given a string containing just the characters ‘(‘...

06 Nov 2021

Jump Game II Problem

LeetCode 45. Given an array of non-negative integers nums, you...

06 Nov 2021

Longest Palindromic Substring Problem

LeetCode 5. Given a string s, return the longest palindromic...

05 Nov 2021

Generate Parentheses Problem

LeetCode 22. Given n pairs of parentheses, write a function...

05 Nov 2021

Tag Array

X Of A Kind In A Deck Of Cards Problem

LeetCode 914. In a deck of cards, each card has...

01 Oct 2022

Word Subsets Problem

LeetCode 916. You are given two string arrays words1 and...

01 Oct 2022

Walking Robot Simulation Problem

LeetCode 874. A robot on an infinite XY-plane starts at...

01 Oct 2022

Vowel Spellchecker Problem

LeetCode 966. Given a wordlist, we want to implement a...

01 Oct 2022

Verifying An Alien Dictionary Problem

LeetCode 953. In an alien language, surprisingly, they also use...

01 Oct 2022

Validate Stack Sequences Problem

LeetCode 946. Given two integer arrays pushed and popped each...

01 Oct 2022

Valid Mountain Array Problem

LeetCode 941. Given an array of integers arr, return true...

01 Oct 2022

Unique Paths III Problem

LeetCode 980. You are given an m x n integer...

01 Oct 2022

Unique Morse Code Words Problem

LeetCode 804. International Morse Code defines a standard encoding where...

01 Oct 2022

Unique Email Addresses Problem

LeetCode 929. Every valid email consists of a local name...

01 Oct 2022

Triples With Bitwise And Equal To Zero Problem

LeetCode 982. Given an integer array nums, return the number...

01 Oct 2022

Transpose Matrix Problem

LeetCode 867. Given a 2D integer array matrix, return the...

01 Oct 2022

Three Equal Parts Problem

LeetCode 927. You are given an array arr which consists...

01 Oct 2022

Tallest Billboard Problem

LeetCode 956. You are installing a billboard and want it...

01 Oct 2022

Surface Area Of 3D Shapes Problem

LeetCode 892. You are given an n x n grid...

01 Oct 2022

Sum Of Subsequence Widths Problem

LeetCode 891. The width of a sequence is the difference...

01 Oct 2022

Sum Of Subarray Minimums Problem

LeetCode 907. Given an array of integers arr, find the...

01 Oct 2022

Sum Of Even Numbers After Queries Problem

LeetCode 985. You are given an integer array nums and...

01 Oct 2022

Subdomain Visit Count Problem

LeetCode 811. A website domain “discuss.leetcode.com” consists of various subdomains....

01 Oct 2022

Subarrays With K Different Integers Problem

LeetCode 992. Given an integer array nums and an integer...

01 Oct 2022

Stone Game Problem

LeetCode 877. Alice and Bob play a game with piles...

01 Oct 2022

Squares Of A Sorted Array Problem

LeetCode 977. Given an integer array nums sorted in non-decreasing...

01 Oct 2022

Split Array With Same Average Problem

LeetCode 805. You are given an integer array nums.

01 Oct 2022

Spiral Matrix III Problem

LeetCode 885. You start at the cell (rStart, cStart) of...

01 Oct 2022

Sort Array By Parity Problem

LeetCode 905. Given an integer array nums, move all the...

01 Oct 2022

Sort Array By Parity II Problem

LeetCode 922. Given an array of integers nums, half of...

01 Oct 2022

Sort An Array Problem

LeetCode 912. Given an array of integers nums, sort the...

01 Oct 2022

Snakes And Ladders Problem

LeetCode 909. You are given an n x n integer...

01 Oct 2022

Smallest Range II Problem

LeetCode 910. You are given an integer array nums and...

01 Oct 2022

Smallest Range I Problem

LeetCode 908. You are given an integer array nums and...

01 Oct 2022

Similar String Groups Problem

LeetCode 839. Two strings Xand Yare similar if we can...

01 Oct 2022

Shortest Subarray With Sum At Least K Problem

LeetCode 862. Given an integer array nums and an integer...

01 Oct 2022

Shortest Distance To A Character Problem

LeetCode 821. Given a string s and a character c...

01 Oct 2022

Shortest Bridge Problem

LeetCode 934. You are given an n x n binary...

01 Oct 2022

Short Encoding Of Words Problem

LeetCode 820. A valid encoding of an array of words...

01 Oct 2022

Shifting Letters Problem

LeetCode 848. You are given a string s of lowercase...

01 Oct 2022

Score After Flipping Matrix Problem

LeetCode 861. You are given an m x n binary...

01 Oct 2022

Satisfiability Of Equality Equations Problem

LeetCode 990. You are given an array of strings equations...

01 Oct 2022

Rotting Oranges Problem

LeetCode 994. You are given an m x n grid...

01 Oct 2022

Rle Iterator Problem

LeetCode 900. We can use run-length encoding (i.e., RLE) to...

01 Oct 2022

Reveal Cards In Increasing Order Problem

LeetCode 950. You are given an integer array deck. There...

01 Oct 2022

Reorder Data In Log Files Problem

LeetCode 937. You are given an array of logs. Each...

01 Oct 2022

Rectangle Area II Problem

LeetCode 850. You are given a 2D array of axis-aligned...

01 Oct 2022

Projection Area Of 3D Shapes Problem

LeetCode 883. You are given an n x n grid...

01 Oct 2022

Profitable Schemes Problem

LeetCode 879. There is a group of n members, and...

01 Oct 2022

Prison Cells After N Days Problem

LeetCode 957. There are 8 prison cells in a row...

01 Oct 2022

Peak Index In A Mountain Array Problem

LeetCode 852. Let’s call an array arr a mountainif the...

01 Oct 2022

Partition Array Into Disjoint Intervals Problem

LeetCode 915. Given an integer array nums, partition it into...

01 Oct 2022

Pancake Sorting Problem

LeetCode 969. Given an array of integers arr, sort the...

01 Oct 2022

Online Election Problem

LeetCode 911. You are given two integer arrays persons and...

01 Oct 2022

Odd Even Jump Problem

LeetCode 975. You are given an integer array arr. From...

01 Oct 2022

Numbers At Most N Given Digit Set Problem

LeetCode 902. Given an array of digits which is sorted...

01 Oct 2022

Number Of Squareful Arrays Problem

LeetCode 996. An array is squareful if the sum of...

01 Oct 2022

Number Of Lines To Write String Problem

LeetCode 806. You are given a string s of lowercase...

01 Oct 2022

Most Profit Assigning Work Problem

LeetCode 826. You have n jobs and m workers. You...

01 Oct 2022

Monotonic Array Problem

LeetCode 896. An array is monotonic if it is either...

01 Oct 2022

Minimum Swaps To Make Sequences Increasing Problem

LeetCode 801. You are given two integer arrays of the...

01 Oct 2022

Minimum Number Of Refueling Stops Problem

LeetCode 871. A car travels from a starting position to...

01 Oct 2022

Minimum Number Of K Consecutive Bit Flips Problem

LeetCode 995. You are given a binary array nums and...

01 Oct 2022

Minimum Increment To Make Array Unique Problem

LeetCode 945. You are given an integer array nums. In...

01 Oct 2022

Minimum Falling Path Sum Problem

LeetCode 931. Given an n x n array of integers...

01 Oct 2022

Minimum Cost To Merge Stones Problem

LeetCode 1000. There are n piles of stones arranged in...

01 Oct 2022

Minimum Cost To Hire K Workers Problem

LeetCode 857. There are n workers. You are given two...

01 Oct 2022

Minimum Cost For Tickets Problem

LeetCode 983. You have planned some train traveling one year...

01 Oct 2022

Minimum Area Rectangle Problem

LeetCode 939. You are given an array of points in...

01 Oct 2022

Minimum Area Rectangle II Problem

LeetCode 963. You are given an array of points in...

01 Oct 2022

Minimize Malware Spread Problem

LeetCode 924. You are given a network of n nodes...

01 Oct 2022

Minimize Malware Spread II Problem

LeetCode 928. You are given a network of n nodes...

01 Oct 2022

Maximum Width Ramp Problem

LeetCode 962. A ramp in an integer array nums is...

01 Oct 2022

Maximum Sum Circular Subarray Problem

LeetCode 918. Given a circular integer array nums of length...

01 Oct 2022

Maximize Distance To Closest Person Problem

LeetCode 849. You are given an array representing a row...

01 Oct 2022

Max Increase To Keep City Skyline Problem

LeetCode 807. There is a city composed of n x...

01 Oct 2022

Making A Large Island Problem

LeetCode 827. You are given an n x n binary...

01 Oct 2022

Magic Squares In Grid Problem

LeetCode 840. A 3 x 3 magic square is a...

01 Oct 2022

Loud And Rich Problem

LeetCode 851. There is a group of n people labeled...

01 Oct 2022

Longest Turbulent Subarray Problem

LeetCode 978. Given an integer array arr, return the length...

01 Oct 2022

Longest Mountain In Array Problem

LeetCode 845. Given an integer array arr, return the length...

01 Oct 2022

Linked List Components Problem

LeetCode 817. You are given the head of a linked...

01 Oct 2022

Length Of Longest Fibonacci Subsequence Problem

LeetCode 873. Given a strictly increasing array arr of positive...

01 Oct 2022

Lemonade Change Problem

LeetCode 860. At a lemonade stand, each lemonade costs $5....

01 Oct 2022

Largest Triangle Area Problem

LeetCode 812. Given an array of points on the X-Y...

01 Oct 2022

Largest Sum Of Averages Problem

LeetCode 813. You are given an integer array nums and...

01 Oct 2022

Largest Perimeter Triangle Problem

LeetCode 976. Given an integer array nums, return the largest...

01 Oct 2022

Largest Component Size By Common Factor Problem

LeetCode 952. You are given an integer array of unique...

01 Oct 2022

Koko Eating Bananas Problem

LeetCode 875. Koko loves to eat bananas. There are n...

01 Oct 2022

K Closest Points To Origin Problem

LeetCode 973. Given an array of points where points[i] =...

01 Oct 2022

Interval List Intersections Problem

LeetCode 986. You are given two lists of closed intervals,...

01 Oct 2022

Image Overlap Problem

LeetCode 835. You are given two images, img1 and img2,...

01 Oct 2022

Hand Of Straights Problem

LeetCode 846. Alice has some number of cards and she...

01 Oct 2022

Guess The Word Problem

LeetCode 843. This is an interactive problem.

01 Oct 2022

Groups Of Special-Equivalent Strings Problem

LeetCode 893. You are given an array of strings of...

01 Oct 2022

Fruit Into Baskets Problem

LeetCode 904. You are visiting a farm that has a...

01 Oct 2022

Friends Of Appropriate Ages Problem

LeetCode 825. There are n persons on a social media...

01 Oct 2022

Flipping An Image Problem

LeetCode 832. Given an n x n binary matrix image,...

01 Oct 2022

Find The Town Judge Problem

LeetCode 997. In a town, there are n people labeled...

01 Oct 2022

Find The Shortest Superstring Problem

LeetCode 943. Given an array of strings words, return the...

01 Oct 2022

Find And Replace Pattern Problem

LeetCode 890. Given a list of strings words and a...

01 Oct 2022

Find And Replace In String Problem

LeetCode 833. You are given a 0-indexed string s that...

01 Oct 2022

Fair Candy Swap Problem

LeetCode 888. Alice and Bob have a different total number...

01 Oct 2022

Expressive Words Problem

LeetCode 809. Sometimes people repeat letters to represent extra feeling....

01 Oct 2022

DI String Match Problem

LeetCode 942. A permutation perm of n + 1 integers...

01 Oct 2022

Delete Columns To Make Sorted Problem

LeetCode 944. You are given an array of n strings...

01 Oct 2022

Delete Columns To Make Sorted III Problem

LeetCode 960. You are given an array of n strings...

01 Oct 2022

Delete Columns To Make Sorted II Problem

LeetCode 955. You are given an array of n strings...

01 Oct 2022

Construct Binary Tree From Preorder And Postorder Traversal Problem

LeetCode 889. Given two integer arrays, preorder and postorder where...

30 Sep 2022

Chalkboard Xor Game Problem

LeetCode 810. You are given an array of integers nums...

30 Sep 2022

Card Flipping Game Problem

LeetCode 822. You are given n cards, with a positive...

30 Sep 2022

Car Fleet Problem

LeetCode 853. There are n cars going to the same...

30 Sep 2022

Bus Routes Problem

LeetCode 815. You are given an array routes representing bus...

30 Sep 2022

Bricks Falling When Hit Problem

LeetCode 803. You are given an m x n binary...

30 Sep 2022

Boats To Save People Problem

LeetCode 881. You are given an array people where people[i]...

30 Sep 2022

Bitwise ORs Of Subarrays Problem

LeetCode 898. We have an array arr of non-negative integers....

30 Sep 2022

Binary Trees With Factors Problem

LeetCode 823. Given an array of unique integers, arr, where...

30 Sep 2022

Binary Subarrays With Sum Problem

LeetCode 930. Given a binary array nums and an integer...

30 Sep 2022

Beautiful Array Problem

LeetCode 932. Given the integer n, return any beautiful array...

30 Sep 2022

Bag Of Tokens Problem

LeetCode 948. You have an initial power of power, an...

30 Sep 2022

Available Captures For Rook Problem

LeetCode 999. On an 8 x 8 chessboard, there is...

30 Sep 2022

Array Of Doubled Pairs Problem

LeetCode 954. Given an integer array of even length arr,...

30 Sep 2022

Advantage Shuffle Problem

LeetCode 870. You are given two integer arrays nums1 and...

30 Sep 2022

Add To Array-Form Of Integer Problem

LeetCode 989. The array-form of an integer num is an...

30 Sep 2022

3Sum With Multiplicity Problem

LeetCode 923. Given an integer array arr, and an integer...

30 Sep 2022

Valid Triangle Number Problem

LeetCode 611. Given an integer array nums, return the number...

28 Sep 2022

Valid Tic-Tac-Toe State Problem

LeetCode 794. Given a Tic-Tac-Toe board as a string array...

28 Sep 2022

Transform To Chessboard Problem

LeetCode 782. You are given an n x n binary...

28 Sep 2022

Toeplitz Matrix Problem

LeetCode 766. Given an m x n matrix, returntrueif the...

28 Sep 2022

Task Scheduler Problem

LeetCode 621. Given a characters array tasks, representing the tasks...

28 Sep 2022

Swim In Rising Water Problem

LeetCode 778. You are given an n x n integer...

28 Sep 2022

Stickers To Spell Word Problem

LeetCode 691. We are given n different types of stickers....

28 Sep 2022

Sliding Puzzle Problem

LeetCode 773. On an 2 x 3 board, there are...

28 Sep 2022

Shopping Offers Problem

LeetCode 638. In LeetCode Store, there are n items to...

28 Sep 2022

Set Mismatch Problem

LeetCode 645. You have a set of integers s, which...

28 Sep 2022

Set Intersection Size At Least Two Problem

LeetCode 757. You are given a 2D integer array intervals...

28 Sep 2022

Rabbits In Forest Problem

LeetCode 781. There is a forest with an unknown number...

28 Sep 2022

Open The Lock Problem

LeetCode 752. You have a lock in front of you...

28 Sep 2022

Find Pivot Index Problem

LeetCode 724. Given an array of integers nums, calculate the...

28 Sep 2022

Exclusive Time Of Functions Problem

LeetCode 636. On a single-threaded CPU, we execute a program...

28 Sep 2022

Escape The Ghosts Problem

LeetCode 789. You are playing a simplified PAC-MAN game on...

28 Sep 2022

Cherry Pickup Problem

LeetCode 741. You are given an n x n grid...

28 Sep 2022

Split Array Into Consecutive Subsequences Problem

LeetCode 659. You are given an integer array nums that...

27 Sep 2022

Smallest Rotation With Highest Score Problem

LeetCode 798. You are given an array nums. You can...

27 Sep 2022

Smallest Range Covering Elements From K Lists Problem

LeetCode 632. You have k lists of sorted integers in...

27 Sep 2022

Shortest Completing Word Problem

LeetCode 748. Given a string licensePlate and an array of...

27 Sep 2022

Remove Comments Problem

LeetCode 722. Given a C++ program, remove comments from it....

27 Sep 2022

Partition To K Equal Sum Subsets Problem

LeetCode 698. Given an integer array nums and an integer...

27 Sep 2022

Number Of Subarrays With Bounded Maximum Problem

LeetCode 795. Given an integer array nums and two integers...

27 Sep 2022

Number Of Longest Increasing Subsequence Problem

LeetCode 673. Given an integer arraynums, return the number of...

27 Sep 2022

Non-Decreasing Array Problem

LeetCode 665. Given an array nums with n integers, your...

27 Sep 2022

Min Cost Climbing Stairs Problem

LeetCode 746. You are given an integer array cost where...

27 Sep 2022

Maximum Sum Of 3 Non-Overlapping Subarrays Problem

LeetCode 689. Given an integer array nums and an integer...

27 Sep 2022

Maximum Product Of Three Numbers Problem

LeetCode 628. Given an integer array nums, find three numbers...

27 Sep 2022

Maximum Length Of Repeated Subarray Problem

LeetCode 718. Given two integer arrays nums1 and nums2, return...

27 Sep 2022

Maximum Length Of Pair Chain Problem

LeetCode 646. You are given an array of n pairs...

27 Sep 2022

Max Chunks To Make Sorted Problem

LeetCode 769. You are given an integer array arr of...

27 Sep 2022

Max Chunks To Make Sorted II Problem

LeetCode 768. You are given an integer array arr.

27 Sep 2022

Longest Continuous Increasing Subsequence Problem

LeetCode 674. Given an unsorted array of integers nums, return...

27 Sep 2022

Image Smoother Problem

LeetCode 661. An image smoother is a filter of the...

27 Sep 2022

Global And Local Inversions Problem

LeetCode 775. You are given an integer array nums of...

27 Sep 2022

Flood Fill Problem

LeetCode 733. An image is represented by an m x...

27 Sep 2022

Find Smallest Letter Greater Than Target Problem

LeetCode 744. Given a characters array letters that is sorted...

27 Sep 2022

Find Duplicate File In System Problem

LeetCode 609. Given a list paths of directory info, including...

27 Sep 2022

Falling Squares Problem

LeetCode 699. There are several squares being dropped onto the...

27 Sep 2022

Design Circular Queue Problem

LeetCode 622. Design your implementation of the circular queue. The...

27 Sep 2022

Design Circular Deque Problem

LeetCode 641. Design your implementation of the circular double-ended queue...

27 Sep 2022

Cut Off Trees For Golf Event Problem

LeetCode 675. You are asked to cut off all the...

27 Sep 2022

Maximum Binary Tree Problem

LeetCode 654. You are given an integer array nums with...

26 Sep 2022

Maximum Average Subarray I Problem

LeetCode 643. You are given an integer array nums consisting...

26 Sep 2022

Max Area Of Island Problem

LeetCode 695. You are given an m x n binary...

26 Sep 2022

Largest Plus Sign Problem

LeetCode 764. You are given an integer n. You have...

26 Sep 2022

Largest Number At Least Twice Of Others Problem

LeetCode 747. You are given an integer array nums where...

26 Sep 2022

K-Th Smallest Prime Fraction Problem

LeetCode 786. You are given a sorted integer array arr...

26 Sep 2022

Find K-Th Smallest Pair Distance Problem

LeetCode 719. The distance of a pair of integers a...

26 Sep 2022

Find K Closest Elements Problem

LeetCode 658. Given a sorted integer array arr, two integers...

26 Sep 2022

Design Hashset Problem

LeetCode 705. Design a HashSet without using any built-in hash...

26 Sep 2022

Design Hashmap Problem

LeetCode 706. Design a HashMap without using any built-in hash...

26 Sep 2022

Delete And Earn Problem

LeetCode 740. You are given an integer array nums. You...

26 Sep 2022

Degree Of An Array Problem

LeetCode 697. Given a non-empty array of non-negative integers nums,...

26 Sep 2022

Daily Temperatures Problem

LeetCode 739. Given an array of integers temperatures represents the...

26 Sep 2022

Course Schedule III Problem

LeetCode 630. There are n different online courses numbered from...

26 Sep 2022

Contain Virus Problem

LeetCode 749. A virus is spreading rapidly, and your task...

26 Sep 2022

Can Place Flowers Problem

LeetCode 605. You have a long flowerbed in which some...

26 Sep 2022

Binary Search Problem

LeetCode 704. Given an array of integers nums which is...

26 Sep 2022

Best Time To Buy And Sell Stock With Transaction Fee Problem

LeetCode 714. You are given an array prices where prices[i]...

26 Sep 2022

Beautiful Arrangement II Problem

LeetCode 667. Given two integers n and k, construct a...

26 Sep 2022

Baseball Game Problem

LeetCode 682. You are keeping score for a baseball game...

26 Sep 2022

Asteroid Collision Problem

LeetCode 735. We are given an array asteroids of integers...

26 Sep 2022

Accounts Merge Problem

LeetCode 721. Given a list of accounts where each element...

26 Sep 2022

24 Game Problem

LeetCode 679. You are given an integer array cards of...

26 Sep 2022

1-Bit And 2-Bit Characters Problem

LeetCode 717. We have two special characters, the first character...

26 Sep 2022

Trapping Rain Water II Problem

LeetCode 407. Given an m x n integer matrix heightMap...

25 Sep 2022

Total Hamming Distance Problem

LeetCode 477. The Hamming distance between two integers is the...

25 Sep 2022

Third Maximum Number Problem

LeetCode 414. Given an integer array nums, return the third...

25 Sep 2022

Teemo Attacking Problem

LeetCode 495. Our hero Teemo is attacking an enemy Ashe...

25 Sep 2022

Super Washing Machines Problem

LeetCode 517. You have n super washing machines on a...

25 Sep 2022

Predict The Winner Problem

LeetCode 486. You are given an integer array nums. Two...

25 Sep 2022

Partition Equal Subset Sum Problem

LeetCode 416. Given a non-empty array nums containing only positive...

25 Sep 2022

Pacific Atlantic Water Flow Problem

LeetCode 417. There is an m x n rectangular island...

25 Sep 2022

IPO Problem

LeetCode 502. Suppose LeetCode will start its IPO soon. In...

25 Sep 2022

Frog Jump Problem

LeetCode 403. A frog is crossing a river. The river...

25 Sep 2022

Erect The Fence Problem

LeetCode 587. You are given an array trees where trees[i]...

25 Sep 2022

Target Sum Problem

LeetCode 494. You are given an integer array nums and...

24 Sep 2022

Split Array Largest Sum Problem

LeetCode 410. Given an array nums which consists of non-negative...

24 Sep 2022

Sliding Window Median Problem

LeetCode 480. The median is the middle value in an...

24 Sep 2022

Single Element In A Sorted Array Problem

LeetCode 540. You are given a sorted array consisting of...

24 Sep 2022

Shortest Unsorted Continuous Subarray Problem

LeetCode 581. Given an integer array nums, you need to...

24 Sep 2022

Reverse Pairs Problem

LeetCode 493. Given an integer array nums, return the number...

24 Sep 2022

Reshape The Matrix Problem

LeetCode 566. In MATLAB, there is a handy function called...

24 Sep 2022

Remove Boxes Problem

LeetCode 546. You are given several boxes with different colors...

24 Sep 2022

Relative Ranks Problem

LeetCode 506. You are given an integer array score of...

24 Sep 2022

Range Addition II Problem

LeetCode 598. You are given an m x n matrix...

24 Sep 2022

Queue Reconstruction By Height Problem

LeetCode 406. You are given an array of people, people,...

24 Sep 2022

Optimal Division Problem

LeetCode 553. You are given an integer array nums. The...

23 Sep 2022

Ones And Zeroes Problem

LeetCode 474. You are given an array of binary strings...

23 Sep 2022

Number Of Boomerangs Problem

LeetCode 447. You are given n points in the plane...

23 Sep 2022

Non-Overlapping Intervals Problem

LeetCode 435. Given an array of intervals intervals where intervals[i]...

23 Sep 2022

Next Greater Element II Problem

LeetCode 503. Given a circular integer array nums (i.e., the...

23 Sep 2022

Next Greater Element I Problem

LeetCode 496. The next greater element of some element x...

23 Sep 2022

Minimum Time Difference Problem

LeetCode 539. Given a list of 24-hour clock time points...

23 Sep 2022

Minimum Number Of Arrows To Burst Balloons Problem

LeetCode 452. There are some spherical balloons taped onto a...

23 Sep 2022

Minimum Moves To Equal Array Elements Problem

LeetCode 453. Given an integer array nums of size n,...

22 Sep 2022

Minimum Moves To Equal Array Elements II Problem

LeetCode 462. Given an integer array nums of size n,...

22 Sep 2022

Minimum Index Sum Of Two Lists Problem

LeetCode 599. Suppose Andy and Doris want to choose a...

22 Sep 2022

Minesweeper Problem

LeetCode 529. Let’s play the minesweeper game!

22 Sep 2022

Max Consecutive Ones Problem

LeetCode 485. Given a binary array nums, return the maximum...

22 Sep 2022

Matchsticks To Square Problem

LeetCode 473. You are given an integer array matchsticks where...

22 Sep 2022

Longest Word In Dictionary Through Deleting Problem

LeetCode 524. Given a string s and a string array...

22 Sep 2022

Longest Uncommon Subsequence II Problem

LeetCode 522. Given an array of strings strs, return the...

22 Sep 2022

Longest Harmonious Subsequence Problem

LeetCode 594. We define a harmonious array as an array...

22 Sep 2022

Keyboard Row Problem

LeetCode 500. Given an array of strings words, return the...

22 Sep 2022

K-Diff Pairs In An Array Problem

LeetCode 532. Given an array of integers nums and an...

22 Sep 2022

Island Perimeter Problem

LeetCode 463. You are given row x col grid representing...

22 Sep 2022

Increasing Subsequences Problem

LeetCode 491. Given an integer array nums, return all the...

22 Sep 2022

Heaters Problem

LeetCode 475. Winter is coming! During the contest, your first...

22 Sep 2022

Find Right Interval Problem

LeetCode 436. You are given an array of intervals, where...

21 Sep 2022

Find All Numbers Disappeared In An Array Problem

LeetCode 448. Given an array nums of n integers where...

21 Sep 2022

Find All Duplicates In An Array Problem

LeetCode 442. Given an integer array nums of length n...

21 Sep 2022

Distribute Candies Problem

LeetCode 575. Alice has n candies, where the i^th candy...

21 Sep 2022

Diagonal Traverse Problem

LeetCode 498. Given an m x n matrix mat, return...

21 Sep 2022

Contiguous Array Problem

LeetCode 525. Given a binary array nums, return the maximum...

21 Sep 2022

Construct Quad Tree Problem

LeetCode 427. Given a n * n matrix grid of...

21 Sep 2022

UTF-8 Validation Problem

LeetCode 393. Given an integer array data representing the data,...

19 Sep 2022

Coin Change II Problem

LeetCode 518. You are given an integer array coins representing...

19 Sep 2022

Circular Array Loop Problem

LeetCode 457. You are playing a game involving a circular...

19 Sep 2022

Brick Wall Problem

LeetCode 554. There is a rectangular brick wall in front...

19 Sep 2022

Beautiful Arrangement Problem

LeetCode 526. Suppose you have n integers labeled 1 through...

19 Sep 2022

Battleships In A Board Problem

LeetCode 419. Given an m x n matrix board where...

19 Sep 2022

Assign Cookies Problem

LeetCode 455. Assume you are an awesome parent and want...

19 Sep 2022

Array Partition I Problem

LeetCode 561. Given an integer array nums of 2n integers,...

19 Sep 2022

Array Nesting Problem

LeetCode 565. You are given an integer array nums of...

19 Sep 2022

Arithmetic Slices Problem

LeetCode 413. An integer array is called arithmetic if it...

19 Sep 2022

Arithmetic Slices II - Subsequence Problem

LeetCode 446. Given an integer array nums, return the number...

19 Sep 2022

132 Pattern Problem

LeetCode 456. Given an arrayof n integers nums, a 132...

19 Sep 2022

01 Matrix Problem

LeetCode 542. Given an m x n binary matrix mat,...

19 Sep 2022

Wiggle Subsequence Problem

LeetCode 376. A wiggle sequence is a sequence where the...

18 Sep 2022

Top K Frequent Elements Problem

LeetCode 347. Given an integer array nums and an integer...

18 Sep 2022

Super Ugly Number Problem

LeetCode 313. A super ugly number is a positive integer...

18 Sep 2022

Summary Ranges Problem

LeetCode 228. You are given a sorted unique integer array...

18 Sep 2022

Sliding Window Maximum Problem

LeetCode 239. You are given an array of integersnums, there...

18 Sep 2022

Single Number III Problem

LeetCode 260. Given an integer array nums, in which exactly...

18 Sep 2022

Shuffle An Array Problem

LeetCode 384. Given an integer array nums, design an algorithm...

18 Sep 2022

Self Crossing Problem

LeetCode 335. You are given an array of integers distance....

18 Sep 2022

Search A 2D Matrix II Problem

LeetCode 240. Write an efficient algorithm that searches for a...

18 Sep 2022

Rotate Function Problem

LeetCode 396. You are given an integer array nums of...

18 Sep 2022

Range Sum Query - Immutable Problem

LeetCode 303. Given an integer array nums, handle multiple queries...

16 Sep 2022

Range Sum Query 2D - Immutable Problem

LeetCode 304. Given a 2D matrix matrix, handle multiple queries...

16 Sep 2022

Product Of Array Except Self Problem

LeetCode 238. Given an integer array nums, return an array...

16 Sep 2022

Perfect Rectangle Problem

LeetCode 391. Given an array rectangles where rectangles[i] = [x_i,...

16 Sep 2022

Peeking Iterator Problem

LeetCode 284. Design an iterator that supports the peek operation...

16 Sep 2022

Patching Array Problem

LeetCode 330. Given a sorted integer array nums and an...

16 Sep 2022

Palindrome Pairs Problem

LeetCode 336. Given a list of unique words, return all...

16 Sep 2022

Move Zeroes Problem

LeetCode 283. Given an integer array nums, move all 0’s...

15 Sep 2022

Missing Number Problem

LeetCode 268. Given an array nums containing n distinct numbers...

15 Sep 2022

Minimum Size Subarray Sum Problem

LeetCode 209. Given an array of positive integers nums and...

15 Sep 2022

Maximum Product Of Word Lengths Problem

LeetCode 318. Given a string array words, return the maximum...

15 Sep 2022

Maximal Square Problem

LeetCode 221. Given an m x n binary matrix filled...

15 Sep 2022

Majority Element II Problem

LeetCode 229. Given an integer array of size n, find...

10 Apr 2022

Longest Increasing Subsequence Problem

LeetCode 300. Given an integer array nums, return the length...

10 Apr 2022

Longest Increasing Path In A Matrix Problem

LeetCode 329. Given an m x n integers matrix, return...

10 Apr 2022

Largest Divisible Subset Problem

LeetCode 368. Given a set of distinct positive integers nums,...

10 Apr 2022

Kth Smallest Element In A Sorted Matrix Problem

LeetCode 378. Given an n x n matrix where each...

10 Apr 2022

Kth Largest Element In An Array Problem

LeetCode 215. Given an integer array nums and an integer...

10 Apr 2022

Intersection Of Two Arrays II Problem

LeetCode 350. Given two integer arrays nums1 and nums2, return...

10 Apr 2022

Insert Delete Getrandom O(1) - Duplicates Allowed Problem

LeetCode 381. RandomizedCollection is a data structure that contains a...

10 Apr 2022

Increasing Triplet Subsequence Problem

LeetCode 334. Given an integer array nums, return true if...

10 Apr 2022

House Robber II Problem

LeetCode 213. You are a professional robber planning to rob...

10 Apr 2022

H-Index Problem

LeetCode 274. Given an array of integers citations where citations[i]...

10 Apr 2022

H-Index II Problem

LeetCode 275. Given an array of integers citations where citations[i]...

10 Apr 2022

Game Of Life Problem

LeetCode 289. The Game of Life, also known simply as...

10 Apr 2022

Find The Duplicate Number Problem

LeetCode 287. Given an array of integers nums containingn +...

10 Apr 2022

Find K Pairs With Smallest Sums Problem

LeetCode 373. You are given two integer arrays nums1 and...

10 Apr 2022

Evaluate Division Problem

LeetCode 399. You are given an array of variable pairs...

10 Apr 2022

Count Primes Problem

LeetCode 204. Given an integer n, return the number of...

10 Apr 2022

Count Of Smaller Numbers After Self Problem

LeetCode 315. You are given an integer array nums and...

10 Apr 2022

Count Of Range Sum Problem

LeetCode 327. Given an integer array nums and two integers...

10 Apr 2022

Contains Duplicate Problem

LeetCode 217. Given an integer array nums, return true if...

10 Apr 2022

Contains Duplicate III Problem

LeetCode 220. Given an integer array nums and two integers...

10 Apr 2022

Contains Duplicate II Problem

LeetCode 219. Given an integer array nums and an integer...

10 Apr 2022

Combination Sum IV Problem

LeetCode 377. Given an array of distinct integers nums and...

10 Apr 2022

Combination Sum III Problem

LeetCode 216. Find all valid combinations of k numbers that...

10 Apr 2022

Coin Change Problem

LeetCode 322. You are given an integer array coins representing...

10 Apr 2022

Burst Balloons Problem

LeetCode 312. You are given n balloons, indexed from 0...

10 Apr 2022

Best Time To Buy And Sell Stock With Cooldown Problem

LeetCode 309. You are given an array prices where prices[i]...

10 Apr 2022

Rotate Array Problem

LeetCode 189. Given an array, rotate the array to the...

04 Dec 2021

Maximum Product Subarray Problem

LeetCode 152. Given an integer array nums, find a contiguous...

04 Dec 2021

Maximum Gap Problem

LeetCode 164. Given an integer array nums, return the maximum...

04 Dec 2021

Majority Element Problem

LeetCode 169. Given an array nums of size n, return...

04 Dec 2021

House Robber Problem

LeetCode 198. You are a professional robber planning to rob...

04 Dec 2021

Find Peak Element Problem

LeetCode 162. A peak element is an element that is...

04 Dec 2021

Find Minimum In Rotated Sorted Array Problem

LeetCode 153. Suppose an array of length n sorted in...

04 Dec 2021

Find Minimum In Rotated Sorted Array II Problem

LeetCode 154. Suppose an array of length n sorted in...

04 Dec 2021

Dungeon Game Problem

LeetCode 174. The demons had captured the princess and imprisoned...

04 Dec 2021

Best Time To Buy And Sell Stock IV Problem

LeetCode 188. You are given an integer array prices where...

04 Dec 2021

Single Number Problem

LeetCode 136. Given a non-empty array of integers nums, every...

03 Dec 2021

Single Number II Problem

LeetCode 137. Given an integer array nums whereevery element appears...

03 Dec 2021

Gas Station Problem

LeetCode 134. There are n gas stations along a circular...

03 Dec 2021

Evaluate Reverse Polish Notation Problem

LeetCode 150. Evaluate the value of an arithmetic expression in...

03 Dec 2021

Candy Problem

LeetCode 135. There are n children standing in a line....

03 Dec 2021

Triangle Problem

LeetCode 120. Given a triangle array, return the minimum path...

29 Nov 2021

Surrounded Regions Problem

LeetCode 130. Given an m x n matrix board containing...

29 Nov 2021

Pascal's Triangle Problem

LeetCode 118. Given an integer numRows, return the first numRows...

29 Nov 2021

Pascal's Triangle II Problem

LeetCode 119. Given an integer rowIndex, return the rowIndex^th (0-indexed)...

29 Nov 2021

Longest Consecutive Sequence Problem

LeetCode 128. Given an unsorted array of integers nums, return...

29 Nov 2021

Best Time To Buy And Sell Stock Problem

LeetCode 121. You are given an array prices where prices[i]...

29 Nov 2021

Best Time To Buy And Sell Stock Iii Problem

LeetCode 123. You are given an array prices where prices[i]...

29 Nov 2021

Best Time To Buy And Sell Stock Ii Problem

LeetCode 122. You are given an integer array prices where...

29 Nov 2021

Convert Sorted Array to Binary Search Tree Problem

LeetCode 108. Given an integer array nums where the elements...

20 Nov 2021

Construct Binary Tree from Preorder and Inorder Traversal Problem

LeetCode 105. Given two integer arrays preorder and inorder where...

20 Nov 2021

Word Search Problem

LeetCode 79. Given an m x n grid of characters...

14 Nov 2021

Subsets Problem

LeetCode 78. Given an integer array nums of unique elements,...

14 Nov 2021

Subsets II Problem

LeetCode 90. Given an integer array nums that may contain...

14 Nov 2021

Search in Rotated Sorted Array II Problem

LeetCode 81. There is an integer array nums sorted in...

14 Nov 2021

Remove Duplicates from Sorted Array II Problem

LeetCode 80. Given an integer array nums sorted in non-decreasing...

14 Nov 2021

Merge Sorted Array Problem

LeetCode 88. You are given two integer arrays nums1 and...

14 Nov 2021

Maximal Rectangle Problem

LeetCode 85. Given a rows x cols binary matrix filled...

14 Nov 2021

Largest Rectangle in Histogram Problem

LeetCode 84. Given an array of integers heights representing the...

14 Nov 2021

Sort Colors Problem

LeetCode 75. Given an array nums with n objects colored...

10 Nov 2021

Set Matrix Zeroes Problem

LeetCode 73. Given an m x n integer matrix matrix,...

10 Nov 2021

Search A 2D Matrix Problem

LeetCode 74. Write an efficient algorithm that searches for a...

10 Nov 2021

Combinations Problem

LeetCode 77. Given two integers n and k, return all...

10 Nov 2021

Plus One Problem

LeetCode 66. You are given a large integer represented as...

09 Nov 2021

Minimum Path Sum Problem

LeetCode 64. Given a m x n grid filled with...

09 Nov 2021

Spiral Matrix Problem

LeetCode 54. Given an m x n matrix, return all...

08 Nov 2021

Spiral Matrix II Problem

LeetCode 59. Given a positive integer n, generate an n...

08 Nov 2021

N-Queens Problem

LeetCode 51. Given an integer n, return all distinct solutions...

08 Nov 2021

N-Queens II Problem

LeetCode 52. Given an integer n, return the number of...

08 Nov 2021

Maximum Subarray Problem

LeetCode 53. Given an integer array nums, find the contiguous...

08 Nov 2021

Jump Game Problem

LeetCode 55. Given an m x n matrix, return all...

08 Nov 2021

Insert Interval Problem

LeetCode 57. Insert newInterval into intervals such that intervals is...

08 Nov 2021

Search in Rotated Sorted Array Problem

LeetCode 36. Determine if a 9 x 9 Sudoku board...

06 Nov 2021

Trapping Rain Water Problem

LeetCode 42. Given n non-negative integers representing an elevation map...

06 Nov 2021

Sudoku Solver Problem

LeetCode 37. Write a program to solve a Sudoku puzzle...

06 Nov 2021

Search in Rotated Sorted Array Problem

LeetCode 33. Given the array nums after the possible rotation...

06 Nov 2021

Rotate Image Problem

LeetCode 48. Determine if a 9 x 9 Sudoku board...

06 Nov 2021

Remove Element Problem

LeetCode 27. Given an integer array nums and an integer...

06 Nov 2021

Permutations Problem

LeetCode 46. Given an array nums of distinct integers, return...

06 Nov 2021

Permutations II Problem

LeetCode 47. Given a collection of numbers, nums, that might...

06 Nov 2021

Next Permutation Problem

LeetCode 31. Implement next permutation, which rearranges numbers into the...

06 Nov 2021

Jump Game II Problem

LeetCode 45. Given an array of non-negative integers nums, you...

06 Nov 2021

First Missing Positive Problem

LeetCode 41. Given an unsorted integer array nums, return the...

06 Nov 2021

Find First and Last Position of Element in Sorted Array Problem

LeetCode 34. Given the array nums after the possible rotation...

06 Nov 2021

Combination Sum Problem

LeetCode 39. Given an array of distinct integers candidates and...

06 Nov 2021

Combination Sum II Problem

LeetCode 40. Given a collection of candidate numbers (candidates) and...

06 Nov 2021

3Sum Closest Problem

LeetCode 16. Given an integer array nums of length n...

06 Nov 2021

Remove Duplicates from Sorted Array Problem

LeetCode 26. Given an integer array nums sorted in non-decreasing...

05 Nov 2021

Tag Math

X Of A Kind In A Deck Of Cards Problem

LeetCode 914. In a deck of cards, each card has...

01 Oct 2022

Three Equal Parts Problem

LeetCode 927. You are given an array arr which consists...

01 Oct 2022

Surface Area Of 3D Shapes Problem

LeetCode 892. You are given an n x n grid...

01 Oct 2022

Super Palindromes Problem

LeetCode 906. Let’s say a positive integer is a super-palindrome...

01 Oct 2022

Super Egg Drop Problem

LeetCode 887. You are given k identical eggs and you...

01 Oct 2022

Sum Of Subsequence Widths Problem

LeetCode 891. The width of a sequence is the difference...

01 Oct 2022

Stone Game Problem

LeetCode 877. Alice and Bob play a game with piles...

01 Oct 2022

Split Array With Same Average Problem

LeetCode 805. You are given an integer array nums.

01 Oct 2022

Soup Servings Problem

LeetCode 808. There are two types of soup, type A...

01 Oct 2022

Smallest Range II Problem

LeetCode 910. You are given an integer array nums and...

01 Oct 2022

Smallest Range I Problem

LeetCode 908. You are given an integer array nums and...

01 Oct 2022

Reordered Power Of 2 Problem

LeetCode 869. You are given an integer n. We reorder...

01 Oct 2022

Rectangle Overlap Problem

LeetCode 836. An axis-aligned rectangle is represented as a list...

01 Oct 2022

Projection Area Of 3D Shapes Problem

LeetCode 883. You are given an n x n grid...

01 Oct 2022

Prison Cells After N Days Problem

LeetCode 957. There are 8 prison cells in a row...

01 Oct 2022

Prime Palindrome Problem

LeetCode 866. Given an integer n, return the smallest prime...

01 Oct 2022

Powerful Integers Problem

LeetCode 970. Given three integers x, y, and bound, return...

01 Oct 2022

Orderly Queue Problem

LeetCode 899. You are given a string s and an...

01 Oct 2022

Numbers At Most N Given Digit Set Problem

LeetCode 902. Given an array of digits which is sorted...

01 Oct 2022

Number Of Squareful Arrays Problem

LeetCode 996. An array is squareful if the sum of...

01 Oct 2022

Number Of Music Playlists Problem

LeetCode 920. Your music player contains n different songs. You...

01 Oct 2022

Nth Magical Number Problem

LeetCode 878. A positive integer is magical if it is...

01 Oct 2022

New 21 Game Problem

LeetCode 837. Alice plays the following game, loosely based on...

01 Oct 2022

Mirror Reflection Problem

LeetCode 858. There is a special square room with mirrors...

01 Oct 2022

Minimum Area Rectangle Problem

LeetCode 939. You are given an array of points in...

01 Oct 2022

Minimum Area Rectangle II Problem

LeetCode 963. You are given an array of points in...

01 Oct 2022

Magic Squares In Grid Problem

LeetCode 840. A 3 x 3 magic square is a...

01 Oct 2022

Least Operators To Express Number Problem

LeetCode 964. Given a single positive integer x, we will...

01 Oct 2022

Largest Triangle Area Problem

LeetCode 812. Given an array of points on the X-Y...

01 Oct 2022

Largest Perimeter Triangle Problem

LeetCode 976. Given an integer array nums, return the largest...

01 Oct 2022

Largest Component Size By Common Factor Problem

LeetCode 952. You are given an integer array of unique...

01 Oct 2022

K Closest Points To Origin Problem

LeetCode 973. Given an array of points where points[i] =...

01 Oct 2022

Guess The Word Problem

LeetCode 843. This is an interactive problem.

01 Oct 2022

Equal Rational Numbers Problem

LeetCode 972. Given two strings s and t, each of...

01 Oct 2022

Consecutive Numbers Sum Problem

LeetCode 829. Given an integer n, return the number of...

30 Sep 2022

Chalkboard Xor Game Problem

LeetCode 810. You are given an array of integers nums...

30 Sep 2022

Cat And Mouse Problem

LeetCode 913. A game on an undirected graph is played...

30 Sep 2022

Broken Calculator Problem

LeetCode 991. There is a broken calculator that has the...

30 Sep 2022

Beautiful Array Problem

LeetCode 932. Given the integer n, return any beautiful array...

30 Sep 2022

Add To Array-Form Of Integer Problem

LeetCode 989. The array-form of an integer num is an...

30 Sep 2022

Transform To Chessboard Problem

LeetCode 782. You are given an n x n binary...

28 Sep 2022

Solve The Equation Problem

LeetCode 640. Solve a given equation and return the value...

28 Sep 2022

Self Dividing Numbers Problem

LeetCode 728. A self-dividing number is a number that is...

28 Sep 2022

Reaching Points Problem

LeetCode 780. Given four integers sx, sy, tx, and ty,...

28 Sep 2022

Random Pick With Blacklist Problem

LeetCode 710. You are given an integer n and an...

28 Sep 2022

Rabbits In Forest Problem

LeetCode 781. There is a forest with an unknown number...

28 Sep 2022

Preimage Size Of Factorial Zeroes Function Problem

LeetCode 793. Let f(x) be the number of zeroes at...

28 Sep 2022

K-Th Symbol In Grammar Problem

LeetCode 779. We build a table of n rows (1-indexed)....

28 Sep 2022

Escape The Ghosts Problem

LeetCode 789. You are playing a simplified PAC-MAN game on...

28 Sep 2022

2 Keys Keyboard Problem

LeetCode 650. There is only one character ‘A’ on the...

28 Sep 2022

Sum Of Square Numbers Problem

LeetCode 633. Given a non-negative integer c, decide whether there’re...

27 Sep 2022

Rotated Digits Problem

LeetCode 788. An integer x is a good if after...

27 Sep 2022

Reach A Number Problem

LeetCode 754. You are standing at position 0 on an...

27 Sep 2022

Prime Number Of Set Bits In Binary Representation Problem

LeetCode 762. Given two integers left and right, return the...

27 Sep 2022

Monotone Increasing Digits Problem

LeetCode 738. An integer has monotone increasing digits if and...

27 Sep 2022

Maximum Product Of Three Numbers Problem

LeetCode 628. Given an integer array nums, find three numbers...

27 Sep 2022

Kth Smallest Number In Multiplication Table Problem

LeetCode 668. Nearly everyone has used the Multiplication Table. The...

27 Sep 2022

Global And Local Inversions Problem

LeetCode 775. You are given an integer array nums of...

27 Sep 2022

Maximum Swap Problem

LeetCode 670. You are given an integer num. You can...

26 Sep 2022

Bulb Switcher II Problem

LeetCode 672. There is a room with n bulbs labeled...

26 Sep 2022

Beautiful Arrangement II Problem

LeetCode 667. Given two integers n and k, construct a...

26 Sep 2022

Basic Calculator IV Problem

LeetCode 770. Given an expression such as expression = “e...

26 Sep 2022

24 Game Problem

LeetCode 679. You are given an integer array cards of...

26 Sep 2022

Total Hamming Distance Problem

LeetCode 477. The Hamming distance between two integers is the...

25 Sep 2022

Random Point In Non-Overlapping Rectangles Problem

LeetCode 497. You are given an array of non-overlapping axis-aligned...

25 Sep 2022

Predict The Winner Problem

LeetCode 486. You are given an integer array nums. Two...

25 Sep 2022

Find The Closest Palindrome Problem

LeetCode 564. Given a string n representing an integer, return...

25 Sep 2022

Erect The Fence Problem

LeetCode 587. You are given an array trees where trees[i]...

25 Sep 2022

Valid Square Problem

LeetCode 593. Given the coordinates of four points in 2D...

24 Sep 2022

Smallest Good Base Problem

LeetCode 483. Given an integer n represented as a string,...

24 Sep 2022

Reconstruct Original Digits From English Problem

LeetCode 423. Given a string s containing an out-of-order English...

24 Sep 2022

Range Addition II Problem

LeetCode 598. You are given an m x n matrix...

24 Sep 2022

Random Pick With Weight Problem

LeetCode 528. You are given a 0-indexed array of positive...

24 Sep 2022

Random Flip Matrix Problem

LeetCode 519. There is an m x n binary grid...

24 Sep 2022

Poor Pigs Problem

LeetCode 458. There are buckets buckets of liquid, where exactly...

24 Sep 2022

Perfect Number Problem

LeetCode 507. A perfect number is a positive integer that...

23 Sep 2022

Optimal Division Problem

LeetCode 553. You are given an integer array nums. The...

23 Sep 2022

Number Of Boomerangs Problem

LeetCode 447. You are given n points in the plane...

23 Sep 2022

Next Greater Element III Problem

LeetCode 556. Given a positive integer n, find the smallest...

23 Sep 2022

Minimum Time Difference Problem

LeetCode 539. Given a list of 24-hour clock time points...

23 Sep 2022

Minimum Moves To Equal Array Elements Problem

LeetCode 453. Given an integer array nums of size n,...

22 Sep 2022

Minimum Moves To Equal Array Elements II Problem

LeetCode 462. Given an integer array nums of size n,...

22 Sep 2022

Largest Palindrome Product Problem

LeetCode 479. Given an integer n, return the largest palindromic...

22 Sep 2022

K-Th Smallest In Lexicographical Order Problem

LeetCode 440. Given two integers n and k, return the...

22 Sep 2022

Implement Rand10() Using Rand7() Problem

LeetCode 470. Given the API rand7() that generates a uniform...

22 Sep 2022

Generate Random Point In A Circle Problem

LeetCode 478. Given the radius and the position of the...

22 Sep 2022

Fraction Addition And Subtraction Problem

LeetCode 592. Given a string expression representing an expression of...

21 Sep 2022

Fibonacci Number Problem

LeetCode 509. The Fibonacci numbers, commonly denoted F(n) form a...

21 Sep 2022

Convert A Number To Hexadecimal Problem

LeetCode 405. Given an integer num, return a string representing...

21 Sep 2022

Construct The Rectangle Problem

LeetCode 492. A web developer needs to know how to...

21 Sep 2022

Complex Number Multiplication Problem

LeetCode 537. A complex number can be represented as a...

21 Sep 2022

Water And Jug Problem Problem

LeetCode 365. You are given two jugs with capacities jug1Capacity...

19 Sep 2022

Fizz Buzz Problem

LeetCode 412. Given an integer n, return a string array...

19 Sep 2022

Can I Win Problem

LeetCode 464. In the “100 game” two players take turns...

19 Sep 2022

Base 7 Problem

LeetCode 504. Given an integer num, return a string of...

19 Sep 2022

Arranging Coins Problem

LeetCode 441. You have n coins and you want to...

19 Sep 2022

Add Two Numbers II Problem

LeetCode 445. You are given two non-empty linked lists representing...

19 Sep 2022

Add Strings Problem

LeetCode 415. Given two non-negative integers, num1 and num2 represented...

19 Sep 2022

Ugly Number Problem

LeetCode 263. An ugly number is a positive integer whose...

18 Sep 2022

Ugly Number II Problem

LeetCode 264. An ugly number is a positive integer whose...

18 Sep 2022

Super Ugly Number Problem

LeetCode 313. A super ugly number is a positive integer...

18 Sep 2022

Super Pow Problem

LeetCode 372. Your task is to calculate a^b mod 1337...

18 Sep 2022

Sum Of Two Integers Problem

LeetCode 371. Given two integers a and b, return the...

18 Sep 2022

Shuffle An Array Problem

LeetCode 384. Given an integer array nums, design an algorithm...

18 Sep 2022

Self Crossing Problem

LeetCode 335. You are given an array of integers distance....

18 Sep 2022

Rotate Function Problem

LeetCode 396. You are given an integer array nums of...

18 Sep 2022

Rectangle Area Problem

LeetCode 223. Given the coordinates of two rectilinear rectangles in...

18 Sep 2022

Random Pick Index Problem

LeetCode 398. Given an integer array nums with possible duplicates,...

16 Sep 2022

Power Of Two Problem

LeetCode 231. Given an integer n, return true if it...

16 Sep 2022

Power Of Three Problem

LeetCode 326. Given an integer n, return true if it...

16 Sep 2022

Power Of Four Problem

LeetCode 342. Given an integer n, return true if it...

16 Sep 2022

Perfect Squares Problem

LeetCode 279. Given an integer n, return the least number...

16 Sep 2022

Number Of Digit One Problem

LeetCode 233. Given an integer n, count the total number...

15 Sep 2022

Nth Digit Problem

LeetCode 400. Given an integer n, return the n^th digit...

15 Sep 2022

Nim Game Problem

LeetCode 292. You are playing the following Nim Game with...

15 Sep 2022

Missing Number Problem

LeetCode 268. Given an array nums containing n distinct numbers...

15 Sep 2022

Linked List Random Node Problem

LeetCode 382. Given a singly linked list, return a random...

10 Apr 2022

Lexicographical Numbers Problem

LeetCode 386. Given an integer n, return all the numbers...

10 Apr 2022

Largest Divisible Subset Problem

LeetCode 368. Given a set of distinct positive integers nums,...

10 Apr 2022

Integer To English Words Problem

LeetCode 273. Convert a non-negative integer num to its English...

10 Apr 2022

Integer Break Problem

LeetCode 343. Given an integer n, break it into the...

10 Apr 2022

Insert Delete Getrandom O(1) - Duplicates Allowed Problem

LeetCode 381. RandomizedCollection is a data structure that contains a...

10 Apr 2022

Happy Number Problem

LeetCode 202. Write an algorithm to determine if a number...

10 Apr 2022

Guess Number Higher Or Lower II Problem

LeetCode 375. We are playing the Guessing Game. The game...

10 Apr 2022

Expression Add Operators Problem

LeetCode 282. Given a string num that contains only digits...

10 Apr 2022

Elimination Game Problem

LeetCode 390. You have a list arr of all integers...

10 Apr 2022

Different Ways To Add Parentheses Problem

LeetCode 241. Given a string expression of numbers and operators,...

10 Apr 2022

Count Primes Problem

LeetCode 204. Given an integer n, return the number of...

10 Apr 2022

Count Numbers With Unique Digits Problem

LeetCode 357. Given an integer n, return the count of...

10 Apr 2022

Bulb Switcher Problem

LeetCode 319. There are n bulbs that are initially off....

10 Apr 2022

Basic Calculator Problem

LeetCode 224. Given a string s representing a valid expression,...

10 Apr 2022

Basic Calculator II Problem

LeetCode 227. Given a string s which represents an expression,...

10 Apr 2022

Add Digits Problem

LeetCode 258. Given an integer num, repeatedly add all its...

10 Apr 2022

Rotate Array Problem

LeetCode 189. Given an array, rotate the array to the...

04 Dec 2021

Fraction To Recurring Decimal Problem

LeetCode 166. Given two integers representing the numerator and denominator...

04 Dec 2021

Factorial Trailing Zeroes Problem

LeetCode 172. Given an integer n, return the number of...

04 Dec 2021

Excel Sheet Column Title Problem

LeetCode 168. Given an integer columnNumber, return its corresponding column...

04 Dec 2021

Excel Sheet Column Number Problem

LeetCode 171. Given a string columnTitle that represents the column...

04 Dec 2021

Max Points On A Line Problem

LeetCode 149. Given an array of points where points[i] =...

03 Dec 2021

Evaluate Reverse Polish Notation Problem

LeetCode 150. Evaluate the value of an arithmetic expression in...

03 Dec 2021

Unique Binary Search Trees Problem

LeetCode 96. Given an integer n, return the number of...

14 Nov 2021

Gray Code Problem

LeetCode 89. Given an integer n, return any valid n-bit...

14 Nov 2021

Unique Paths Problem

LeetCode 62. A robot is located at the top-left corner...

09 Nov 2021

Unique Paths II Problem

LeetCode 63. A robot is located at the top-left corner...

09 Nov 2021

Plus One Problem

LeetCode 66. You are given a large integer represented as...

09 Nov 2021

Climbing Stairs Problem

LeetCode 70. You are climbing a staircase. It takes n...

09 Nov 2021

Permutation Sequence Problem

LeetCode 60. Given n and k, return the kth permutation...

08 Nov 2021

Rotate Image Problem

LeetCode 48. Determine if a 9 x 9 Sudoku board...

06 Nov 2021

Pow(x,n) Problem

LeetCode 50. Determine if a 9 x 9 Sudoku board...

06 Nov 2021

Palindrome Number Problem

LeetCode 9. Given an integer x, return true if x...

06 Nov 2021

Multiply Strings Problem

LeetCode 43. Given two non-negative integers num1 and num2 represented...

06 Nov 2021

Integer to Roman Problem

LeetCode 12. Given an integer, convert it to a roman...

06 Nov 2021

Divide Two Integers Problem

LeetCode 29. Write the code that will take a string...

06 Nov 2021

Roman to Integer Problem

LeetCode 13. Given a roman numeral, convert it to an...

05 Nov 2021

Reverse Integer Problem

LeetCode 7. Given a signed 32-bit integer x, return x...

05 Nov 2021

Tag Recursion

All Possible Full Binary Trees Problem

LeetCode 894. Given an integer n, return a list of...

30 Sep 2022

Special Binary String Problem

LeetCode 761. Special binary strings are binary strings with the...

28 Sep 2022

Parse Lisp Expression Problem

LeetCode 736. You are given a string expression representing a...

28 Sep 2022

K-Th Symbol In Grammar Problem

LeetCode 779. We build a table of n rows (1-indexed)....

28 Sep 2022

Basic Calculator IV Problem

LeetCode 770. Given an expression such as expression = “e...

26 Sep 2022

Predict The Winner Problem

LeetCode 486. You are given an integer array nums. Two...

25 Sep 2022

Fibonacci Number Problem

LeetCode 509. The Fibonacci numbers, commonly denoted F(n) form a...

21 Sep 2022

Remove Linked List Elements Problem

LeetCode 203. Given the head of a linked list and...

18 Sep 2022

Power Of Two Problem

LeetCode 231. Given an integer n, return true if it...

16 Sep 2022

Power Of Three Problem

LeetCode 326. Given an integer n, return true if it...

16 Sep 2022

Power Of Four Problem

LeetCode 342. Given an integer n, return true if it...

16 Sep 2022

Number Of Digit One Problem

LeetCode 233. Given an integer n, count the total number...

15 Sep 2022

Integer To English Words Problem

LeetCode 273. Convert a non-negative integer num to its English...

10 Apr 2022

Elimination Game Problem

LeetCode 390. You have a list arr of all integers...

10 Apr 2022

Different Ways To Add Parentheses Problem

LeetCode 241. Given a string expression of numbers and operators,...

10 Apr 2022

Decode String Problem

LeetCode 394. Given an encoded string, return its decoded string....

10 Apr 2022

Basic Calculator Problem

LeetCode 224. Given a string s representing a valid expression,...

10 Apr 2022

Reorder List Problem

LeetCode 143. You are given the head of a singly...

03 Dec 2021

Permutation Sequence Problem

LeetCode 60. Given n and k, return the kth permutation...

08 Nov 2021

Wildcard Matching Problem

LeetCode 44. Write the code that will take a string...

06 Nov 2021

Reverse Nodes in k-Group Problem

LeetCode 25. Given a linked list, reverse the nodes of...

06 Nov 2021

Regular Expression Matching Problem

LeetCode 10. Given an input string s and a pattern...

06 Nov 2021

Pow(x,n) Problem

LeetCode 50. Determine if a 9 x 9 Sudoku board...

06 Nov 2021

Swap Nodes in Pairs Problem

LeetCode 24. Given a linked list, swap every two adjacent...

05 Nov 2021

Tag Stack

Validate Stack Sequences Problem

LeetCode 946. Given two integer arrays pushed and popped each...

01 Oct 2022

Sum Of Subarray Minimums Problem

LeetCode 907. Given an array of integers arr, find the...

01 Oct 2022

Stamping The Sequence Problem

LeetCode 936. You are given two strings stamp and target....

01 Oct 2022

Score Of Parentheses Problem

LeetCode 856. Given a balanced parentheses string s, return the...

01 Oct 2022

Online Stock Span Problem

LeetCode 901. Design an algorithm that collects daily price quotes...

01 Oct 2022

Odd Even Jump Problem

LeetCode 975. You are given an integer array arr. From...

01 Oct 2022

Minimum Add To Make Parentheses Valid Problem

LeetCode 921. A parentheses string is valid if and only...

01 Oct 2022

Maximum Width Ramp Problem

LeetCode 962. A ramp in an integer array nums is...

01 Oct 2022

Maximum Frequency Stack Problem

LeetCode 895. Design a stack-like data structure to push elements...

01 Oct 2022

Increasing Order Search Tree Problem

LeetCode 897. Given the root of a binary search tree,...

01 Oct 2022

Decoded String At Index Problem

LeetCode 880. You are given an encoded string s. To...

01 Oct 2022

Car Fleet Problem

LeetCode 853. There are n cars going to the same...

30 Sep 2022

Backspace String Compare Problem

LeetCode 844. Given two strings s and t, return true...

30 Sep 2022

Valid Parenthesis String Problem

LeetCode 678. Given a string s containing only three types...

28 Sep 2022

Parse Lisp Expression Problem

LeetCode 736. You are given a string expression representing a...

28 Sep 2022

Exclusive Time Of Functions Problem

LeetCode 636. On a single-threaded CPU, we execute a program...

28 Sep 2022

Number Of Atoms Problem

LeetCode 726. Given a string formula representing a chemical formula,return...

27 Sep 2022

Max Chunks To Make Sorted Problem

LeetCode 769. You are given an integer array arr of...

27 Sep 2022

Max Chunks To Make Sorted II Problem

LeetCode 768. You are given an integer array arr.

27 Sep 2022

Maximum Binary Tree Problem

LeetCode 654. You are given an integer array nums with...

26 Sep 2022

Daily Temperatures Problem

LeetCode 739. Given an array of integers temperatures represents the...

26 Sep 2022

Basic Calculator IV Problem

LeetCode 770. Given an expression such as expression = “e...

26 Sep 2022

Baseball Game Problem

LeetCode 682. You are keeping score for a baseball game...

26 Sep 2022

Asteroid Collision Problem

LeetCode 735. We are given an array asteroids of integers...

26 Sep 2022

Tag Validator Problem

LeetCode 591. Given a string representing a code snippet, implement...

25 Sep 2022

Shortest Unsorted Continuous Subarray Problem

LeetCode 581. Given an integer array nums, you need to...

24 Sep 2022

Remove K Digits Problem

LeetCode 402. Given string num representing a non-negative integer num,...

24 Sep 2022

Next Greater Element II Problem

LeetCode 503. Given a circular integer array nums (i.e., the...

23 Sep 2022

Next Greater Element I Problem

LeetCode 496. The next greater element of some element x...

23 Sep 2022

N-Ary Tree Preorder Traversal Problem

LeetCode 589. Given the root of an n-ary tree, return...

23 Sep 2022

N-Ary Tree Postorder Traversal Problem

LeetCode 590. Given the root of an n-ary tree, return...

23 Sep 2022

Add Two Numbers II Problem

LeetCode 445. You are given two non-empty linked lists representing...

19 Sep 2022

132 Pattern Problem

LeetCode 456. Given an arrayof n integers nums, a 132...

19 Sep 2022

Verify Preorder Serialization Of A Binary Tree Problem

LeetCode 331. One way to serialize a binary tree is...

18 Sep 2022

Remove Duplicate Letters Problem

LeetCode 316. Given a string s, remove duplicate letters so...

18 Sep 2022

Mini Parser Problem

LeetCode 385. Given a string s represents the serialization of...

15 Sep 2022

Longest Absolute File Path Problem

LeetCode 388. Suppose we have a file system that stores...

10 Apr 2022

Implement Stack Using Queues Problem

LeetCode 225. Implement a last-in-first-out (LIFO) stack using only two...

10 Apr 2022

Implement Queue Using Stacks Problem

LeetCode 232. Implement a first in first out (FIFO) queue...

10 Apr 2022

Flatten Nested List Iterator Problem

LeetCode 341. You are given a nested list of integers...

10 Apr 2022

Decode String Problem

LeetCode 394. Given an encoded string, return its decoded string....

10 Apr 2022

Create Maximum Number Problem

LeetCode 321. You are given two integer arrays nums1 and...

10 Apr 2022

Basic Calculator Problem

LeetCode 224. Given a string s representing a valid expression,...

10 Apr 2022

Basic Calculator II Problem

LeetCode 227. Given a string s which represents an expression,...

10 Apr 2022

Min Stack Problem

LeetCode 155. Design a stack that supports push, pop, top,...

04 Dec 2021

Binary Search Tree Iterator Problem

LeetCode 173. Implement the BSTIterator class that represents an iterator...

04 Dec 2021

Reorder List Problem

LeetCode 143. You are given the head of a singly...

03 Dec 2021

Evaluate Reverse Polish Notation Problem

LeetCode 150. Evaluate the value of an arithmetic expression in...

03 Dec 2021

Binary Tree Preorder Traversal Problem

LeetCode 144. Given the root of a binary tree, return...

03 Dec 2021

Binary Tree Postorder Traversal Problem

LeetCode 145. Given the root of abinary tree, return the...

03 Dec 2021

Flatten Binary Tree To Linked List Problem

LeetCode 114. Given the root of a binary tree, flatten...

29 Nov 2021

Maximal Rectangle Problem

LeetCode 85. Given a rows x cols binary matrix filled...

14 Nov 2021

Largest Rectangle in Histogram Problem

LeetCode 84. Given an array of integers heights representing the...

14 Nov 2021

Binary Tree Inorder Traversal Problem

LeetCode 94. Given an m x n grid of characters...

14 Nov 2021

Simplify Path Problem

LeetCode 71. Given a string path, which is an absolute...

10 Nov 2021

Trapping Rain Water Problem

LeetCode 42. Given n non-negative integers representing an elevation map...

06 Nov 2021

Valid Parentheses Problem

LeetCode 20. Given a string s containing just the characters...

05 Nov 2021

Tag Sorting

Sum Of Subsequence Widths Problem

LeetCode 891. The width of a sequence is the difference...

01 Oct 2022

Squares Of A Sorted Array Problem

LeetCode 977. Given an integer array nums sorted in non-decreasing...

01 Oct 2022

Sort Array By Parity Problem

LeetCode 905. Given an integer array nums, move all the...

01 Oct 2022

Sort Array By Parity II Problem

LeetCode 922. Given an array of integers nums, half of...

01 Oct 2022

Sort An Array Problem

LeetCode 912. Given an array of integers nums, sort the...

01 Oct 2022

Smallest Range II Problem

LeetCode 910. You are given an integer array nums and...

01 Oct 2022

Reveal Cards In Increasing Order Problem

LeetCode 950. You are given an integer array deck. There...

01 Oct 2022

Reordered Power Of 2 Problem

LeetCode 869. You are given an integer n. We reorder...

01 Oct 2022

Reorder Data In Log Files Problem

LeetCode 937. You are given an array of logs. Each...

01 Oct 2022

Pancake Sorting Problem

LeetCode 969. Given an array of integers arr, sort the...

01 Oct 2022

Orderly Queue Problem

LeetCode 899. You are given a string s and an...

01 Oct 2022

Most Profit Assigning Work Problem

LeetCode 826. You have n jobs and m workers. You...

01 Oct 2022

Minimum Increment To Make Array Unique Problem

LeetCode 945. You are given an integer array nums. In...

01 Oct 2022

Minimum Cost To Hire K Workers Problem

LeetCode 857. There are n workers. You are given two...

01 Oct 2022

Minimum Area Rectangle Problem

LeetCode 939. You are given an array of points in...

01 Oct 2022

Largest Perimeter Triangle Problem

LeetCode 976. Given an integer array nums, return the largest...

01 Oct 2022

K Closest Points To Origin Problem

LeetCode 973. Given an array of points where points[i] =...

01 Oct 2022

Hand Of Straights Problem

LeetCode 846. Alice has some number of cards and she...

01 Oct 2022

Friends Of Appropriate Ages Problem

LeetCode 825. There are n persons on a social media...

01 Oct 2022

Find And Replace In String Problem

LeetCode 833. You are given a 0-indexed string s that...

01 Oct 2022

Fair Candy Swap Problem

LeetCode 888. Alice and Bob have a different total number...

01 Oct 2022

Car Fleet Problem

LeetCode 853. There are n cars going to the same...

30 Sep 2022

Boats To Save People Problem

LeetCode 881. You are given an array people where people[i]...

30 Sep 2022

Bag Of Tokens Problem

LeetCode 948. You have an initial power of power, an...

30 Sep 2022

Array Of Doubled Pairs Problem

LeetCode 954. Given an integer array of even length arr,...

30 Sep 2022

Advantage Shuffle Problem

LeetCode 870. You are given two integer arrays nums1 and...

30 Sep 2022

3Sum With Multiplicity Problem

LeetCode 923. Given an integer array arr, and an integer...

30 Sep 2022

Valid Triangle Number Problem

LeetCode 611. Given an integer array nums, return the number...

28 Sep 2022

Top K Frequent Words Problem

LeetCode 692. Given an array of strings words and an...

28 Sep 2022

Task Scheduler Problem

LeetCode 621. Given a characters array tasks, representing the tasks...

28 Sep 2022

Set Mismatch Problem

LeetCode 645. You have a set of integers s, which...

28 Sep 2022

Set Intersection Size At Least Two Problem

LeetCode 757. You are given a 2D integer array intervals...

28 Sep 2022

Reorganize String Problem

LeetCode 767. Given a string s, rearrange the characters of...

28 Sep 2022

Random Pick With Blacklist Problem

LeetCode 710. You are given an integer n and an...

28 Sep 2022

Smallest Range Covering Elements From K Lists Problem

LeetCode 632. You have k lists of sorted integers in...

27 Sep 2022

Number Of Matching Subsequences Problem

LeetCode 792. Given a string s and an array of...

27 Sep 2022

Number Of Atoms Problem

LeetCode 726. Given a string formula representing a chemical formula,return...

27 Sep 2022

Maximum Product Of Three Numbers Problem

LeetCode 628. Given an integer array nums, find three numbers...

27 Sep 2022

Maximum Length Of Pair Chain Problem

LeetCode 646. You are given an array of n pairs...

27 Sep 2022

Max Chunks To Make Sorted Problem

LeetCode 769. You are given an integer array arr of...

27 Sep 2022

Max Chunks To Make Sorted II Problem

LeetCode 768. You are given an integer array arr.

27 Sep 2022

Largest Number At Least Twice Of Others Problem

LeetCode 747. You are given an integer array nums where...

26 Sep 2022

K-Th Smallest Prime Fraction Problem

LeetCode 786. You are given a sorted integer array arr...

26 Sep 2022

Find K-Th Smallest Pair Distance Problem

LeetCode 719. The distance of a pair of integers a...

26 Sep 2022

Find K Closest Elements Problem

LeetCode 658. Given a sorted integer array arr, two integers...

26 Sep 2022

Custom Sort String Problem

LeetCode 791. You are given two strings order and s....

26 Sep 2022

Third Maximum Number Problem

LeetCode 414. Given an integer array nums, return the third...

25 Sep 2022

IPO Problem

LeetCode 502. Suppose LeetCode will start its IPO soon. In...

25 Sep 2022

Sort Characters By Frequency Problem

LeetCode 451. Given a string s, sort it in decreasing...

24 Sep 2022

Shortest Unsorted Continuous Subarray Problem

LeetCode 581. Given an integer array nums, you need to...

24 Sep 2022

Relative Ranks Problem

LeetCode 506. You are given an integer array score of...

24 Sep 2022

Queue Reconstruction By Height Problem

LeetCode 406. You are given an array of people, people,...

24 Sep 2022

Non-Overlapping Intervals Problem

LeetCode 435. Given an array of intervals intervals where intervals[i]...

23 Sep 2022

Minimum Time Difference Problem

LeetCode 539. Given a list of 24-hour clock time points...

23 Sep 2022

Minimum Number Of Arrows To Burst Balloons Problem

LeetCode 452. There are some spherical balloons taped onto a...

23 Sep 2022

Minimum Moves To Equal Array Elements II Problem

LeetCode 462. Given an integer array nums of size n,...

22 Sep 2022

Longest Word In Dictionary Through Deleting Problem

LeetCode 524. Given a string s and a string array...

22 Sep 2022

Longest Uncommon Subsequence II Problem

LeetCode 522. Given an array of strings strs, return the...

22 Sep 2022

Longest Harmonious Subsequence Problem

LeetCode 594. We define a harmonious array as an array...

22 Sep 2022

K-Diff Pairs In An Array Problem

LeetCode 532. Given an array of integers nums and an...

22 Sep 2022

Heaters Problem

LeetCode 475. Winter is coming! During the contest, your first...

22 Sep 2022

Find Right Interval Problem

LeetCode 436. You are given an array of intervals, where...

21 Sep 2022

Assign Cookies Problem

LeetCode 455. Assume you are an awesome parent and want...

19 Sep 2022

Array Partition I Problem

LeetCode 561. Given an integer array nums of 2n integers,...

19 Sep 2022

Valid Anagram Problem

LeetCode 242. Given two strings s and t, return true...

18 Sep 2022

Top K Frequent Elements Problem

LeetCode 347. Given an integer array nums and an integer...

18 Sep 2022

Missing Number Problem

LeetCode 268. Given an array nums containing n distinct numbers...

15 Sep 2022

Majority Element II Problem

LeetCode 229. Given an integer array of size n, find...

10 Apr 2022

Largest Divisible Subset Problem

LeetCode 368. Given a set of distinct positive integers nums,...

10 Apr 2022

Kth Smallest Element In A Sorted Matrix Problem

LeetCode 378. Given an n x n matrix where each...

10 Apr 2022

Kth Largest Element In An Array Problem

LeetCode 215. Given an integer array nums and an integer...

10 Apr 2022

Intersection Of Two Arrays II Problem

LeetCode 350. Given two integer arrays nums1 and nums2, return...

10 Apr 2022

H-Index Problem

LeetCode 274. Given an array of integers citations where citations[i]...

10 Apr 2022

Find The Difference Problem

LeetCode 389. You are given two strings s and t....

10 Apr 2022

Find Median From Data Stream Problem

LeetCode 295. The median is the middle value in an...

10 Apr 2022

Contains Duplicate Problem

LeetCode 217. Given an integer array nums, return true if...

10 Apr 2022

Contains Duplicate III Problem

LeetCode 220. Given an integer array nums and two integers...

10 Apr 2022

Maximum Gap Problem

LeetCode 164. Given an integer array nums, return the maximum...

04 Dec 2021

Majority Element Problem

LeetCode 169. Given an array nums of size n, return...

04 Dec 2021

Largest Number Problem

LeetCode 179. Given a list of non-negative integers nums, arrange...

04 Dec 2021

Sort List Problem

LeetCode 148. Given the head of a linked list, return...

03 Dec 2021

Insertion Sort List Problem

LeetCode 147. Given the head of a singly linked list,...

03 Dec 2021

Merge Sorted Array Problem

LeetCode 88. You are given two integer arrays nums1 and...

14 Nov 2021

Group Anagrams Problem

LeetCode 49. Given an array of strings strs, group the...

06 Nov 2021

3Sum Closest Problem

LeetCode 16. Given an integer array nums of length n...

06 Nov 2021

Tag Bit Manipulation

Unique Paths III Problem

LeetCode 980. You are given an m x n integer...

01 Oct 2022

Triples With Bitwise And Equal To Zero Problem

LeetCode 982. Given an integer array nums, return the number...

01 Oct 2022

Split Array With Same Average Problem

LeetCode 805. You are given an integer array nums.

01 Oct 2022

Shortest Path Visiting All Nodes Problem

LeetCode 847. You have an undirected, connected graph of n...

01 Oct 2022

Shortest Path To Get All Keys Problem

LeetCode 864. You are given an m x n grid...

01 Oct 2022

Score After Flipping Matrix Problem

LeetCode 861. You are given an m x n binary...

01 Oct 2022

Prison Cells After N Days Problem

LeetCode 957. There are 8 prison cells in a row...

01 Oct 2022

Number Of Squareful Arrays Problem

LeetCode 996. An array is squareful if the sum of...

01 Oct 2022

Minimum Number Of K Consecutive Bit Flips Problem

LeetCode 995. You are given a binary array nums and...

01 Oct 2022

Find The Shortest Superstring Problem

LeetCode 943. Given an array of strings words, return the...

01 Oct 2022

Chalkboard Xor Game Problem

LeetCode 810. You are given an array of integers nums...

30 Sep 2022

Bitwise ORs Of Subarrays Problem

LeetCode 898. We have an array arr of non-negative integers....

30 Sep 2022

Binary Gap Problem

LeetCode 868. Given a positive integer n, find and return...

30 Sep 2022

Transform To Chessboard Problem

LeetCode 782. You are given an n x n binary...

28 Sep 2022

Stickers To Spell Word Problem

LeetCode 691. We are given n different types of stickers....

28 Sep 2022

Shopping Offers Problem

LeetCode 638. In LeetCode Store, there are n items to...

28 Sep 2022

Set Mismatch Problem

LeetCode 645. You have a set of integers s, which...

28 Sep 2022

Pyramid Transition Matrix Problem

LeetCode 756. You are stacking blocks to form a pyramid....

28 Sep 2022

K-Th Symbol In Grammar Problem

LeetCode 779. We build a table of n rows (1-indexed)....

28 Sep 2022

Prime Number Of Set Bits In Binary Representation Problem

LeetCode 762. Given two integers left and right, return the...

27 Sep 2022

Partition To K Equal Sum Subsets Problem

LeetCode 698. Given an integer array nums and an integer...

27 Sep 2022

Letter Case Permutation Problem

LeetCode 784. Given a string s, we can transform every...

27 Sep 2022

Bulb Switcher II Problem

LeetCode 672. There is a room with n bulbs labeled...

26 Sep 2022

Binary Number With Alternating Bits Problem

LeetCode 693. Given a positive integer, check whether it has...

26 Sep 2022

Total Hamming Distance Problem

LeetCode 477. The Hamming distance between two integers is the...

25 Sep 2022

Number Complement Problem

LeetCode 476. The complement of an integer is the integer...

23 Sep 2022

Matchsticks To Square Problem

LeetCode 473. You are given an integer array matchsticks where...

22 Sep 2022

Increasing Subsequences Problem

LeetCode 491. Given an integer array nums, return all the...

22 Sep 2022

Hamming Distance Problem

LeetCode 461. The Hamming distance between two integers is the...

22 Sep 2022

Convert A Number To Hexadecimal Problem

LeetCode 405. Given an integer num, return a string representing...

21 Sep 2022

UTF-8 Validation Problem

LeetCode 393. Given an integer array data representing the data,...

19 Sep 2022

Can I Win Problem

LeetCode 464. In the “100 game” two players take turns...

19 Sep 2022

Binary Watch Problem

LeetCode 401. A binary watch has 4 LEDs on the...

19 Sep 2022

Sum Of Two Integers Problem

LeetCode 371. Given two integers a and b, return the...

18 Sep 2022

Single Number III Problem

LeetCode 260. Given an integer array nums, in which exactly...

18 Sep 2022

Power Of Two Problem

LeetCode 231. Given an integer n, return true if it...

16 Sep 2022

Power Of Four Problem

LeetCode 342. Given an integer n, return true if it...

16 Sep 2022

Missing Number Problem

LeetCode 268. Given an array nums containing n distinct numbers...

15 Sep 2022

Maximum Product Of Word Lengths Problem

LeetCode 318. Given a string array words, return the maximum...

15 Sep 2022

Integer Replacement Problem

LeetCode 397. Given a positive integer n,you can apply one...

10 Apr 2022

Find The Duplicate Number Problem

LeetCode 287. Given an array of integers nums containingn +...

10 Apr 2022

Find The Difference Problem

LeetCode 389. You are given two strings s and t....

10 Apr 2022

Counting Bits Problem

LeetCode 338. Given an integer n, return an array ans...

10 Apr 2022

Bitwise And Of Numbers Range Problem

LeetCode 201. Given two integers left and right that represent...

10 Apr 2022

Reverse Bits Problem

LeetCode 190. Reverse bits of a given 32 bits unsigned...

04 Dec 2021

Repeated DNA Sequences Problem

LeetCode 187. The DNA sequence is composed of a series...

04 Dec 2021

Number Of 1 Bits Problem

LeetCode 191. Write a function that takes an unsigned integer...

04 Dec 2021

Single Number Problem

LeetCode 136. Given a non-empty array of integers nums, every...

03 Dec 2021

Single Number II Problem

LeetCode 137. Given an integer array nums whereevery element appears...

03 Dec 2021

Subsets II Problem

LeetCode 90. Given an integer array nums that may contain...

14 Nov 2021

Gray Code Problem

LeetCode 89. Given an integer n, return any valid n-bit...

14 Nov 2021

Divide Two Integers Problem

LeetCode 29. Write the code that will take a string...

06 Nov 2021

Tag Stack Leetcode

Longest Valid Parentheses Problem

LeetCode 32. Given a string containing just the characters ‘(‘...

06 Nov 2021

Tag Divide and Conquer

Sort An Array Problem

LeetCode 912. Given an array of integers nums, sort the...

01 Oct 2022

Maximum Sum Circular Subarray Problem

LeetCode 918. Given a circular integer array nums of length...

01 Oct 2022

K Closest Points To Origin Problem

LeetCode 973. Given an array of points where points[i] =...

01 Oct 2022

Construct Binary Tree From Preorder And Postorder Traversal Problem

LeetCode 889. Given two integer arrays, preorder and postorder where...

30 Sep 2022

Beautiful Array Problem

LeetCode 932. Given the integer n, return any beautiful array...

30 Sep 2022

Maximum Binary Tree Problem

LeetCode 654. You are given an integer array nums with...

26 Sep 2022

Reverse Pairs Problem

LeetCode 493. Given an integer array nums, return the number...

24 Sep 2022

Logical Or Of Two Binary Grids Represented As Quad-Trees Problem

LeetCode 558. A Binary Matrix is a matrix in which...

22 Sep 2022

Construct Quad Tree Problem

LeetCode 427. Given a n * n matrix grid of...

21 Sep 2022

Top K Frequent Elements Problem

LeetCode 347. Given an integer array nums and an integer...

18 Sep 2022

Super Pow Problem

LeetCode 372. Your task is to calculate a^b mod 1337...

18 Sep 2022

Search A 2D Matrix II Problem

LeetCode 240. Write an efficient algorithm that searches for a...

18 Sep 2022

Longest Substring With At Least K Repeating Characters Problem

LeetCode 395. Given a string s and an integer k,...

10 Apr 2022

Kth Largest Element In An Array Problem

LeetCode 215. Given an integer array nums and an integer...

10 Apr 2022

Count Of Smaller Numbers After Self Problem

LeetCode 315. You are given an integer array nums and...

10 Apr 2022

Count Of Range Sum Problem

LeetCode 327. Given an integer array nums and two integers...

10 Apr 2022

Reverse Bits Problem

LeetCode 190. Reverse bits of a given 32 bits unsigned...

04 Dec 2021

Majority Element Problem

LeetCode 169. Given an array nums of size n, return...

04 Dec 2021

Sort List Problem

LeetCode 148. Given the head of a linked list, return...

03 Dec 2021

Convert Sorted List To Binary Search Tree Problem

LeetCode 109. Given the head of a singly linked list...

29 Nov 2021

Convert Sorted Array to Binary Search Tree Problem

LeetCode 108. Given an integer array nums where the elements...

20 Nov 2021

Construct Binary Tree from Preorder and Inorder Traversal Problem

LeetCode 105. Given two integer arrays preorder and inorder where...

20 Nov 2021

Maximum Subarray Problem

LeetCode 53. Given an integer array nums, find the contiguous...

08 Nov 2021

Tag Matrix

Unique Paths III Problem

LeetCode 980. You are given an m x n integer...

01 Oct 2022

Transpose Matrix Problem

LeetCode 867. Given a 2D integer array matrix, return the...

01 Oct 2022

Surface Area Of 3D Shapes Problem

LeetCode 892. You are given an n x n grid...

01 Oct 2022

Spiral Matrix III Problem

LeetCode 885. You start at the cell (rStart, cStart) of...

01 Oct 2022

Snakes And Ladders Problem

LeetCode 909. You are given an n x n integer...

01 Oct 2022

Shortest Bridge Problem

LeetCode 934. You are given an n x n binary...

01 Oct 2022

Score After Flipping Matrix Problem

LeetCode 861. You are given an m x n binary...

01 Oct 2022

Rotting Oranges Problem

LeetCode 994. You are given an m x n grid...

01 Oct 2022

Projection Area Of 3D Shapes Problem

LeetCode 883. You are given an n x n grid...

01 Oct 2022

Minimum Falling Path Sum Problem

LeetCode 931. Given an n x n array of integers...

01 Oct 2022

Minimize Malware Spread Problem

LeetCode 924. You are given a network of n nodes...

01 Oct 2022

Minimize Malware Spread II Problem

LeetCode 928. You are given a network of n nodes...

01 Oct 2022

Max Increase To Keep City Skyline Problem

LeetCode 807. There is a city composed of n x...

01 Oct 2022

Making A Large Island Problem

LeetCode 827. You are given an n x n binary...

01 Oct 2022

Magic Squares In Grid Problem

LeetCode 840. A 3 x 3 magic square is a...

01 Oct 2022

Image Overlap Problem

LeetCode 835. You are given two images, img1 and img2,...

01 Oct 2022

Flipping An Image Problem

LeetCode 832. Given an n x n binary matrix image,...

01 Oct 2022

Bricks Falling When Hit Problem

LeetCode 803. You are given an m x n binary...

30 Sep 2022

Available Captures For Rook Problem

LeetCode 999. On an 8 x 8 chessboard, there is...

30 Sep 2022

Transform To Chessboard Problem

LeetCode 782. You are given an n x n binary...

28 Sep 2022

Toeplitz Matrix Problem

LeetCode 766. Given an m x n matrix, returntrueif the...

28 Sep 2022

Swim In Rising Water Problem

LeetCode 778. You are given an n x n integer...

28 Sep 2022

Sliding Puzzle Problem

LeetCode 773. On an 2 x 3 board, there are...

28 Sep 2022

Cherry Pickup Problem

LeetCode 741. You are given an n x n grid...

28 Sep 2022

Image Smoother Problem

LeetCode 661. An image smoother is a filter of the...

27 Sep 2022

Flood Fill Problem

LeetCode 733. An image is represented by an m x...

27 Sep 2022

Cut Off Trees For Golf Event Problem

LeetCode 675. You are asked to cut off all the...

27 Sep 2022

Max Area Of Island Problem

LeetCode 695. You are given an m x n binary...

26 Sep 2022

Contain Virus Problem

LeetCode 749. A virus is spreading rapidly, and your task...

26 Sep 2022

Trapping Rain Water II Problem

LeetCode 407. Given an m x n integer matrix heightMap...

25 Sep 2022

Pacific Atlantic Water Flow Problem

LeetCode 417. There is an m x n rectangular island...

25 Sep 2022

Reshape The Matrix Problem

LeetCode 566. In MATLAB, there is a handy function called...

24 Sep 2022

Minesweeper Problem

LeetCode 529. Let’s play the minesweeper game!

22 Sep 2022

Island Perimeter Problem

LeetCode 463. You are given row x col grid representing...

22 Sep 2022

Diagonal Traverse Problem

LeetCode 498. Given an m x n matrix mat, return...

21 Sep 2022

Construct Quad Tree Problem

LeetCode 427. Given a n * n matrix grid of...

21 Sep 2022

Battleships In A Board Problem

LeetCode 419. Given an m x n matrix board where...

19 Sep 2022

01 Matrix Problem

LeetCode 542. Given an m x n binary matrix mat,...

19 Sep 2022

Search A 2D Matrix II Problem

LeetCode 240. Write an efficient algorithm that searches for a...

18 Sep 2022

Range Sum Query 2D - Immutable Problem

LeetCode 304. Given a 2D matrix matrix, handle multiple queries...

16 Sep 2022

Maximal Square Problem

LeetCode 221. Given an m x n binary matrix filled...

15 Sep 2022

Longest Increasing Path In A Matrix Problem

LeetCode 329. Given an m x n integers matrix, return...

10 Apr 2022

Kth Smallest Element In A Sorted Matrix Problem

LeetCode 378. Given an n x n matrix where each...

10 Apr 2022

Game Of Life Problem

LeetCode 289. The Game of Life, also known simply as...

10 Apr 2022

Dungeon Game Problem

LeetCode 174. The demons had captured the princess and imprisoned...

04 Dec 2021

Surrounded Regions Problem

LeetCode 130. Given an m x n matrix board containing...

29 Nov 2021

Spiral Matrix Problem

LeetCode 54. Given an m x n matrix, return all...

08 Nov 2021

Spiral Matrix II Problem

LeetCode 59. Given a positive integer n, generate an n...

08 Nov 2021

Tag Git Commit

How to Modify Existing Unpushed Commit Messages

Short answers to the question how to modify existing unpushed...

09 Nov 2021

Tag Git Revert

How to Revert a Git Repository to a Previous Commit

Short answers to the question how to revert a git...

09 Nov 2021

Tag Git Pull

What is the Difference Between Git Pull and Git Fetch

Short answers to the question what is the difference between...

09 Nov 2021

Tag Hash Table String

Minimum Window Substring Problem

LeetCode 76. Given two strings s and t of lengths...

10 Nov 2021

Vertical Order Traversal Of A Binary Tree Problem

LeetCode 987. Given the root of a binary tree, calculate...

01 Oct 2022

Univalued Binary Tree Problem

LeetCode 965. A binary tree is uni-valued if every node...

01 Oct 2022

Sum Of Distances In Tree Problem

LeetCode 834. There is an undirected connected tree with n...

01 Oct 2022

Smallest Subtree With All The Deepest Nodes Problem

LeetCode 865. Given the root of a binary tree, the...

01 Oct 2022

Smallest String Starting From Leaf Problem

LeetCode 988. You are given the root of a binary...

01 Oct 2022

Similar String Groups Problem

LeetCode 839. Two strings Xand Yare similar if we can...

01 Oct 2022

Shortest Bridge Problem

LeetCode 934. You are given an n x n binary...

01 Oct 2022

Regions Cut By Slashes Problem

LeetCode 959. An n x n grid is composed of...

01 Oct 2022

Range Sum Of BST Problem

LeetCode 938. Given the root node of a binary search...

01 Oct 2022

Possible Bipartition Problem

LeetCode 886. We want to split a group of n...

01 Oct 2022

Most Stones Removed With Same Row Or Column Problem

LeetCode 947. On a 2D plane, we place n stones...

01 Oct 2022

Minimize Malware Spread Problem

LeetCode 924. You are given a network of n nodes...

01 Oct 2022

Minimize Malware Spread II Problem

LeetCode 928. You are given a network of n nodes...

01 Oct 2022

Making A Large Island Problem

LeetCode 827. You are given an n x n binary...

01 Oct 2022

Loud And Rich Problem

LeetCode 851. There is a group of n people labeled...

01 Oct 2022

Leaf-Similar Trees Problem

LeetCode 872. Consider all the leaves of a binary tree,...

01 Oct 2022

Keys And Rooms Problem

LeetCode 841. There are n rooms labeled from 0 to...

01 Oct 2022

Increasing Order Search Tree Problem

LeetCode 897. Given the root of a binary search tree,...

01 Oct 2022

Flip Equivalent Binary Trees Problem

LeetCode 951. For a binary tree T, we can define...

01 Oct 2022

Flip Binary Tree To Match Preorder Traversal Problem

LeetCode 971. You are given the root of a binary...

01 Oct 2022

Find Eventual Safe States Problem

LeetCode 802. There is a directed graph of n nodes...

01 Oct 2022

Distribute Coins In Binary Tree Problem

LeetCode 979. You are given the root of a binary...

01 Oct 2022

Cousins In Binary Tree Problem

LeetCode 993. Given the root of a binary tree with...

01 Oct 2022

Binary Tree Pruning Problem

LeetCode 814. Given the root of a binary tree, return...

30 Sep 2022

Binary Tree Cameras Problem

LeetCode 968. You are given the root of a binary...

30 Sep 2022

All Nodes Distance K In Binary Tree Problem

LeetCode 863. Given the root of a binary tree, the...

30 Sep 2022

Swim In Rising Water Problem

LeetCode 778. You are given an n x n integer...

28 Sep 2022

Redundant Connection Problem

LeetCode 684. In this problem, a tree is an undirected...

28 Sep 2022

Redundant Connection II Problem

LeetCode 685. In this problem, a rooted tree is a...

28 Sep 2022

Pyramid Transition Matrix Problem

LeetCode 756. You are stacking blocks to form a pyramid....

28 Sep 2022

Network Delay Time Problem

LeetCode 743. You are given a network of n nodes,...

28 Sep 2022

Two Sum IV - Input Is A BST Problem

LeetCode 653. Given the root of a Binary Search Tree...

27 Sep 2022

Trim A Binary Search Tree Problem

LeetCode 669. Given the root of a binary search tree...

27 Sep 2022

Second Minimum Node In A Binary Tree Problem

LeetCode 671. Given a non-empty special binary tree consisting of...

27 Sep 2022

Print Binary Tree Problem

LeetCode 655. Given the root of a binary tree, construct...

27 Sep 2022

Minimum Distance Between BST Nodes Problem

LeetCode 783. Given the root of a Binary Search Tree...

27 Sep 2022

Merge Two Binary Trees Problem

LeetCode 617. You are given two binary trees root1 and...

27 Sep 2022

Maximum Width Of Binary Tree Problem

LeetCode 662. Given the root of a binary tree, return...

27 Sep 2022

Longest Univalue Path Problem

LeetCode 687. Given the root of a binary tree, return...

27 Sep 2022

Is Graph Bipartite? Problem

LeetCode 785. There is an undirected graph with n nodes,...

27 Sep 2022

Flood Fill Problem

LeetCode 733. An image is represented by an m x...

27 Sep 2022

Max Area Of Island Problem

LeetCode 695. You are given an m x n binary...

26 Sep 2022

Find Duplicate Subtrees Problem

LeetCode 652. Given the rootof a binary tree, return all...

26 Sep 2022

Employee Importance Problem

LeetCode 690. You have a data structure of employee information,...

26 Sep 2022

Cracking The Safe Problem

LeetCode 753. There is a safe protected by a password....

26 Sep 2022

Couples Holding Hands Problem

LeetCode 765. There are n couples sitting in 2n seats...

26 Sep 2022

Contain Virus Problem

LeetCode 749. A virus is spreading rapidly, and your task...

26 Sep 2022

Construct String From Binary Tree Problem

LeetCode 606. Given the root of a binary tree, construct...

26 Sep 2022

Cheapest Flights Within K Stops Problem

LeetCode 787. There are n cities connected by some number...

26 Sep 2022

Bulb Switcher II Problem

LeetCode 672. There is a room with n bulbs labeled...

26 Sep 2022

Average Of Levels In Binary Tree Problem

LeetCode 637. Given the root of a binary tree, return...

26 Sep 2022

All Paths From Source To Target Problem

LeetCode 797. Given a directed acyclic graph (DAG) of n...

26 Sep 2022

Add One Row To Tree Problem

LeetCode 623. Given the root of a binary tree and...

26 Sep 2022

Accounts Merge Problem

LeetCode 721. Given a list of accounts where each element...

26 Sep 2022

Pacific Atlantic Water Flow Problem

LeetCode 417. There is an m x n rectangular island...

25 Sep 2022

Freedom Trail Problem

LeetCode 514. In the video game Fallout 4, the quest...

25 Sep 2022

Sum Of Left Leaves Problem

LeetCode 404. Given the root of a binary tree, return...

24 Sep 2022

Subtree Of Another Tree Problem

LeetCode 572. Given the roots of two binary trees root...

24 Sep 2022

Serialize And Deserialize BST Problem

LeetCode 449. Serialization is converting a data structure or object...

24 Sep 2022

Path Sum III Problem

LeetCode 437. Given the root of a binary tree and...

23 Sep 2022

Number Of Provinces Problem

LeetCode 547. There are n cities. Some of them are...

23 Sep 2022

N-Ary Tree Preorder Traversal Problem

LeetCode 589. Given the root of an n-ary tree, return...

23 Sep 2022

N-Ary Tree Postorder Traversal Problem

LeetCode 590. Given the root of an n-ary tree, return...

23 Sep 2022

Most Frequent Subtree Sum Problem

LeetCode 508. Given the root of a binary tree, return...

23 Sep 2022

Minimum Absolute Difference In BST Problem

LeetCode 530. Given the root of a Binary Search Tree...

22 Sep 2022

Minesweeper Problem

LeetCode 529. Let’s play the minesweeper game!

22 Sep 2022

Maximum Depth Of N-Ary Tree Problem

LeetCode 559. Given a n-ary tree, find its maximum depth....

22 Sep 2022

Island Perimeter Problem

LeetCode 463. You are given row x col grid representing...

22 Sep 2022

Flatten A Multilevel Doubly Linked List Problem

LeetCode 430. You are given a doubly linked list, which...

21 Sep 2022

Find Mode In Binary Search Tree Problem

LeetCode 501. Given the root of a binary search tree...

21 Sep 2022

Find Largest Value In Each Tree Row Problem

LeetCode 515. Given the root of a binary tree, return...

21 Sep 2022

Find Bottom Left Tree Value Problem

LeetCode 513. Given the root of a binary tree, return...

21 Sep 2022

Convert BST To Greater Tree Problem

LeetCode 538. Given the root of a Binary Search Tree...

21 Sep 2022

Water And Jug Problem Problem

LeetCode 365. You are given two jugs with capacities jug1Capacity...

19 Sep 2022

Can I Win Problem

LeetCode 464. In the “100 game” two players take turns...

19 Sep 2022

Binary Tree Tilt Problem

LeetCode 563. Given the root of a binary tree, return...

19 Sep 2022

Battleships In A Board Problem

LeetCode 419. Given an m x n matrix board where...

19 Sep 2022

Array Nesting Problem

LeetCode 565. You are given an integer array nums of...

19 Sep 2022

Minimum Height Trees Problem

LeetCode 310. A tree is an undirected graph in which...

15 Sep 2022

Mini Parser Problem

LeetCode 385. Given a string s represents the serialization of...

15 Sep 2022

Lowest Common Ancestor Of A Binary Tree Problem

LeetCode 236. Given a binary tree, find the lowest common...

10 Apr 2022

Lowest Common Ancestor Of A Binary Search Tree Problem

LeetCode 235. Given a binary search tree (BST), find the...

10 Apr 2022

Longest Increasing Path In A Matrix Problem

LeetCode 329. Given an m x n integers matrix, return...

10 Apr 2022

Longest Absolute File Path Problem

LeetCode 388. Suppose we have a file system that stores...

10 Apr 2022

Lexicographical Numbers Problem

LeetCode 386. Given an integer n, return all the numbers...

10 Apr 2022

Kth Smallest Element In A BST Problem

LeetCode 230. Given the root of a binary search tree,...

10 Apr 2022

Invert Binary Tree Problem

LeetCode 226. Given the root of a binary tree, invert...

10 Apr 2022

House Robber III Problem

LeetCode 337. The thief has found himself a new place...

10 Apr 2022

Flatten Nested List Iterator Problem

LeetCode 341. You are given a nested list of integers...

10 Apr 2022

Evaluate Division Problem

LeetCode 399. You are given an array of variable pairs...

10 Apr 2022

Design Add And Search Words Data Structure Problem

LeetCode 211. Design a data structure that supports adding new...

10 Apr 2022

Course Schedule Problem

LeetCode 207. There are a total of numCourses courses you...

10 Apr 2022

Course Schedule II Problem

LeetCode 210. There are a total of numCourses courses you...

10 Apr 2022

Count Complete Tree Nodes Problem

LeetCode 222. Given the root of a complete binary tree,...

10 Apr 2022

Binary Tree Paths Problem

LeetCode 257. Given the root of a binary tree, return...

10 Apr 2022

Binary Tree Right Side View Problem

LeetCode 199. Given the root of a binary tree, imagine...

04 Dec 2021

Clone Graph Problem

LeetCode 133. Given a reference of a node in a...

03 Dec 2021

Binary Tree Preorder Traversal Problem

LeetCode 144. Given the root of a binary tree, return...

03 Dec 2021

Binary Tree Postorder Traversal Problem

LeetCode 145. Given the root of abinary tree, return the...

03 Dec 2021

Surrounded Regions Problem

LeetCode 130. Given an m x n matrix board containing...

29 Nov 2021

Sum Root To Leaf Numbers Problem

LeetCode 129. You are given the root of a binary...

29 Nov 2021

Populating Next Right Pointers In Each Node Problem

LeetCode 116. You are given a perfect binary tree where...

29 Nov 2021

Populating Next Right Pointers In Each Node II Problem

LeetCode 117. Given a binary tree, populate each next pointer...

29 Nov 2021

Path Sum Problem

LeetCode 112. Given the root of a binary tree and...

29 Nov 2021

Path Sum II Problem

LeetCode 113. Given the root of a binary tree and...

29 Nov 2021

Minimum Depth Of Binary Tree Problem

LeetCode 111. Given a binary tree, find its minimum depth....

29 Nov 2021

Flatten Binary Tree To Linked List Problem

LeetCode 114. Given the root of a binary tree, flatten...

29 Nov 2021

Binary Tree Maximum Path Sum Problem

LeetCode 124. A path in a binary tree is a...

29 Nov 2021

Balanced Binary Tree Problem

LeetCode 110. Given a binary tree, determine if it is...

29 Nov 2021

Symmetric Tree Problem

LeetCode 101. Given the root of a binary tree, check...

20 Nov 2021

Maximum Depth of Binary Tree Problem

LeetCode 104. Given the root of a binary tree, return...

20 Nov 2021

Construct Binary Tree From Inorder And Postorder Traversal Problem

LeetCode 106. Given two integer arrays inorder and postorder where...

20 Nov 2021

Validate Binary Search Tree Problem

LeetCode 98. Given the root of a binary tree, determine...

16 Nov 2021

Same Tree Problem

LeetCode 100. Given the roots of two binary trees p...

16 Nov 2021

Recover Binary Search Tree Problem

LeetCode 99. You are given the root of a binary...

16 Nov 2021

Binary Tree Inorder Traversal Problem

LeetCode 94. Given an m x n grid of characters...

14 Nov 2021

Tag Binary Tree

Vertical Order Traversal Of A Binary Tree Problem

LeetCode 987. Given the root of a binary tree, calculate...

01 Oct 2022

Univalued Binary Tree Problem

LeetCode 965. A binary tree is uni-valued if every node...

01 Oct 2022

Smallest Subtree With All The Deepest Nodes Problem

LeetCode 865. Given the root of a binary tree, the...

01 Oct 2022

Smallest String Starting From Leaf Problem

LeetCode 988. You are given the root of a binary...

01 Oct 2022

Range Sum Of BST Problem

LeetCode 938. Given the root node of a binary search...

01 Oct 2022

Maximum Binary Tree II Problem

LeetCode 998. A maximum tree is a tree where every...

01 Oct 2022

Leaf-Similar Trees Problem

LeetCode 872. Consider all the leaves of a binary tree,...

01 Oct 2022

Flip Equivalent Binary Trees Problem

LeetCode 951. For a binary tree T, we can define...

01 Oct 2022

Flip Binary Tree To Match Preorder Traversal Problem

LeetCode 971. You are given the root of a binary...

01 Oct 2022

Distribute Coins In Binary Tree Problem

LeetCode 979. You are given the root of a binary...

01 Oct 2022

Cousins In Binary Tree Problem

LeetCode 993. Given the root of a binary tree with...

01 Oct 2022

Construct Binary Tree From Preorder And Postorder Traversal Problem

LeetCode 889. Given two integer arrays, preorder and postorder where...

30 Sep 2022

Complete Binary Tree Inserter Problem

LeetCode 919. A complete binary tree is a binary tree...

30 Sep 2022

Check Completeness Of A Binary Tree Problem

LeetCode 958. Given the root of a binary tree, determine...

30 Sep 2022

Binary Tree Pruning Problem

LeetCode 814. Given the root of a binary tree, return...

30 Sep 2022

Binary Tree Cameras Problem

LeetCode 968. You are given the root of a binary...

30 Sep 2022

All Possible Full Binary Trees Problem

LeetCode 894. Given an integer n, return a list of...

30 Sep 2022

All Nodes Distance K In Binary Tree Problem

LeetCode 863. Given the root of a binary tree, the...

30 Sep 2022

Two Sum IV - Input Is A BST Problem

LeetCode 653. Given the root of a Binary Search Tree...

27 Sep 2022

Trim A Binary Search Tree Problem

LeetCode 669. Given the root of a binary search tree...

27 Sep 2022

Second Minimum Node In A Binary Tree Problem

LeetCode 671. Given a non-empty special binary tree consisting of...

27 Sep 2022

Search In A Binary Search Tree Problem

LeetCode 700. You are given the root of a binary...

27 Sep 2022

Print Binary Tree Problem

LeetCode 655. Given the root of a binary tree, construct...

27 Sep 2022

Minimum Distance Between BST Nodes Problem

LeetCode 783. Given the root of a Binary Search Tree...

27 Sep 2022

Merge Two Binary Trees Problem

LeetCode 617. You are given two binary trees root1 and...

27 Sep 2022

Maximum Width Of Binary Tree Problem

LeetCode 662. Given the root of a binary tree, return...

27 Sep 2022

Longest Univalue Path Problem

LeetCode 687. Given the root of a binary tree, return...

27 Sep 2022

Maximum Binary Tree Problem

LeetCode 654. You are given an integer array nums with...

26 Sep 2022

Kth Largest Element In A Stream Problem

LeetCode 703. Design a class to find the k^th largest...

26 Sep 2022

Insert Into A Binary Search Tree Problem

LeetCode 701. You are given the root node of a...

26 Sep 2022

Find Duplicate Subtrees Problem

LeetCode 652. Given the rootof a binary tree, return all...

26 Sep 2022

Construct String From Binary Tree Problem

LeetCode 606. Given the root of a binary tree, construct...

26 Sep 2022

Average Of Levels In Binary Tree Problem

LeetCode 637. Given the root of a binary tree, return...

26 Sep 2022

Add One Row To Tree Problem

LeetCode 623. Given the root of a binary tree and...

26 Sep 2022

Sum Of Left Leaves Problem

LeetCode 404. Given the root of a binary tree, return...

24 Sep 2022

Subtree Of Another Tree Problem

LeetCode 572. Given the roots of two binary trees root...

24 Sep 2022

Serialize And Deserialize BST Problem

LeetCode 449. Serialization is converting a data structure or object...

24 Sep 2022

Path Sum III Problem

LeetCode 437. Given the root of a binary tree and...

23 Sep 2022

Minimum Absolute Difference In BST Problem

LeetCode 530. Given the root of a Binary Search Tree...

22 Sep 2022

Find Mode In Binary Search Tree Problem

LeetCode 501. Given the root of a binary search tree...

21 Sep 2022

Find Largest Value In Each Tree Row Problem

LeetCode 515. Given the root of a binary tree, return...

21 Sep 2022

Find Bottom Left Tree Value Problem

LeetCode 513. Given the root of a binary tree, return...

21 Sep 2022

Delete Node In A BST Problem

LeetCode 450. Given a root node reference of a BST...

21 Sep 2022

Convert BST To Greater Tree Problem

LeetCode 538. Given the root of a Binary Search Tree...

21 Sep 2022

Binary Tree Tilt Problem

LeetCode 563. Given the root of a binary tree, return...

19 Sep 2022

Verify Preorder Serialization Of A Binary Tree Problem

LeetCode 331. One way to serialize a binary tree is...

18 Sep 2022

Lowest Common Ancestor Of A Binary Tree Problem

LeetCode 236. Given a binary tree, find the lowest common...

10 Apr 2022

Lowest Common Ancestor Of A Binary Search Tree Problem

LeetCode 235. Given a binary search tree (BST), find the...

10 Apr 2022

Kth Smallest Element In A BST Problem

LeetCode 230. Given the root of a binary search tree,...

10 Apr 2022

Invert Binary Tree Problem

LeetCode 226. Given the root of a binary tree, invert...

10 Apr 2022

House Robber III Problem

LeetCode 337. The thief has found himself a new place...

10 Apr 2022

Count Complete Tree Nodes Problem

LeetCode 222. Given the root of a complete binary tree,...

10 Apr 2022

Binary Tree Paths Problem

LeetCode 257. Given the root of a binary tree, return...

10 Apr 2022

Binary Tree Right Side View Problem

LeetCode 199. Given the root of a binary tree, imagine...

04 Dec 2021

Binary Search Tree Iterator Problem

LeetCode 173. Implement the BSTIterator class that represents an iterator...

04 Dec 2021

Binary Tree Preorder Traversal Problem

LeetCode 144. Given the root of a binary tree, return...

03 Dec 2021

Binary Tree Postorder Traversal Problem

LeetCode 145. Given the root of abinary tree, return the...

03 Dec 2021

Sum Root To Leaf Numbers Problem

LeetCode 129. You are given the root of a binary...

29 Nov 2021

Populating Next Right Pointers In Each Node Problem

LeetCode 116. You are given a perfect binary tree where...

29 Nov 2021

Populating Next Right Pointers In Each Node II Problem

LeetCode 117. Given a binary tree, populate each next pointer...

29 Nov 2021

Path Sum Problem

LeetCode 112. Given the root of a binary tree and...

29 Nov 2021

Path Sum II Problem

LeetCode 113. Given the root of a binary tree and...

29 Nov 2021

Minimum Depth Of Binary Tree Problem

LeetCode 111. Given a binary tree, find its minimum depth....

29 Nov 2021

Flatten Binary Tree To Linked List Problem

LeetCode 114. Given the root of a binary tree, flatten...

29 Nov 2021

Convert Sorted List To Binary Search Tree Problem

LeetCode 109. Given the head of a singly linked list...

29 Nov 2021

Binary Tree Maximum Path Sum Problem

LeetCode 124. A path in a binary tree is a...

29 Nov 2021

Balanced Binary Tree Problem

LeetCode 110. Given a binary tree, determine if it is...

29 Nov 2021

Symmetric Tree Problem

LeetCode 101. Given the root of a binary tree, check...

20 Nov 2021

Maximum Depth of Binary Tree Problem

LeetCode 104. Given the root of a binary tree, return...

20 Nov 2021

Construct Binary Tree from Preorder and Inorder Traversal Problem

LeetCode 105. Given two integer arrays preorder and inorder where...

20 Nov 2021

Construct Binary Tree From Inorder And Postorder Traversal Problem

LeetCode 106. Given two integer arrays inorder and postorder where...

20 Nov 2021

Binary Tree Zigzag Level Order Traversal Problem

LeetCode 103. Given the root of a binary tree, return...

20 Nov 2021

Binary Tree Level Order Traversal Problem

LeetCode 102. Given the root of a binary tree, return...

20 Nov 2021

Binary Tree Level Order Traversal II Problem

LeetCode 107. Given the root of a binary tree, return...

20 Nov 2021

Validate Binary Search Tree Problem

LeetCode 98. Given the root of a binary tree, determine...

16 Nov 2021

Same Tree Problem

LeetCode 100. Given the roots of two binary trees p...

16 Nov 2021

Recover Binary Search Tree Problem

LeetCode 99. You are given the root of a binary...

16 Nov 2021

Unique Binary Search Trees Problem

LeetCode 96. Given an integer n, return the number of...

14 Nov 2021

Unique Binary Search Trees II Problem

LeetCode 95. Given an integer n, return all the structurally...

14 Nov 2021

Binary Tree Inorder Traversal Problem

LeetCode 94. Given an m x n grid of characters...

14 Nov 2021

Tag Binary Search Tree

Range Sum Of BST Problem

LeetCode 938. Given the root node of a binary search...

01 Oct 2022

Increasing Order Search Tree Problem

LeetCode 897. Given the root of a binary search tree,...

01 Oct 2022

Two Sum IV - Input Is A BST Problem

LeetCode 653. Given the root of a Binary Search Tree...

27 Sep 2022

Trim A Binary Search Tree Problem

LeetCode 669. Given the root of a binary search tree...

27 Sep 2022

Search In A Binary Search Tree Problem

LeetCode 700. You are given the root of a binary...

27 Sep 2022

Minimum Distance Between BST Nodes Problem

LeetCode 783. Given the root of a Binary Search Tree...

27 Sep 2022

Kth Largest Element In A Stream Problem

LeetCode 703. Design a class to find the k^th largest...

26 Sep 2022

Insert Into A Binary Search Tree Problem

LeetCode 701. You are given the root node of a...

26 Sep 2022

Serialize And Deserialize BST Problem

LeetCode 449. Serialization is converting a data structure or object...

24 Sep 2022

Minimum Absolute Difference In BST Problem

LeetCode 530. Given the root of a Binary Search Tree...

22 Sep 2022

Find Mode In Binary Search Tree Problem

LeetCode 501. Given the root of a binary search tree...

21 Sep 2022

Delete Node In A BST Problem

LeetCode 450. Given a root node reference of a BST...

21 Sep 2022

Convert BST To Greater Tree Problem

LeetCode 538. Given the root of a Binary Search Tree...

21 Sep 2022

Lowest Common Ancestor Of A Binary Search Tree Problem

LeetCode 235. Given a binary search tree (BST), find the...

10 Apr 2022

Kth Smallest Element In A BST Problem

LeetCode 230. Given the root of a binary search tree,...

10 Apr 2022

Binary Search Tree Iterator Problem

LeetCode 173. Implement the BSTIterator class that represents an iterator...

04 Dec 2021

Convert Sorted List To Binary Search Tree Problem

LeetCode 109. Given the head of a singly linked list...

29 Nov 2021

Convert Sorted Array to Binary Search Tree Problem

LeetCode 108. Given an integer array nums where the elements...

20 Nov 2021

Validate Binary Search Tree Problem

LeetCode 98. Given the root of a binary tree, determine...

16 Nov 2021

Same Tree Problem

LeetCode 100. Given the roots of two binary trees p...

16 Nov 2021

Recover Binary Search Tree Problem

LeetCode 99. You are given the root of a binary...

16 Nov 2021

Unique Binary Search Trees Problem

LeetCode 96. Given an integer n, return the number of...

14 Nov 2021

Unique Binary Search Trees II Problem

LeetCode 95. Given an integer n, return all the structurally...

14 Nov 2021

Vertical Order Traversal Of A Binary Tree Problem

LeetCode 987. Given the root of a binary tree, calculate...

01 Oct 2022

Univalued Binary Tree Problem

LeetCode 965. A binary tree is uni-valued if every node...

01 Oct 2022

Snakes And Ladders Problem

LeetCode 909. You are given an n x n integer...

01 Oct 2022

Smallest Subtree With All The Deepest Nodes Problem

LeetCode 865. Given the root of a binary tree, the...

01 Oct 2022

Similar String Groups Problem

LeetCode 839. Two strings Xand Yare similar if we can...

01 Oct 2022

Shortest Path Visiting All Nodes Problem

LeetCode 847. You have an undirected, connected graph of n...

01 Oct 2022

Shortest Path To Get All Keys Problem

LeetCode 864. You are given an m x n grid...

01 Oct 2022

Shortest Bridge Problem

LeetCode 934. You are given an n x n binary...

01 Oct 2022

Rotting Oranges Problem

LeetCode 994. You are given an m x n grid...

01 Oct 2022

Regions Cut By Slashes Problem

LeetCode 959. An n x n grid is composed of...

01 Oct 2022

Possible Bipartition Problem

LeetCode 886. We want to split a group of n...

01 Oct 2022

Numbers With Same Consecutive Differences Problem

LeetCode 967. Return all non-negative integers of length n such...

01 Oct 2022

Minimize Malware Spread Problem

LeetCode 924. You are given a network of n nodes...

01 Oct 2022

Minimize Malware Spread II Problem

LeetCode 928. You are given a network of n nodes...

01 Oct 2022

Making A Large Island Problem

LeetCode 827. You are given an n x n binary...

01 Oct 2022

Keys And Rooms Problem

LeetCode 841. There are n rooms labeled from 0 to...

01 Oct 2022

K-Similar Strings Problem

LeetCode 854. Strings s1 and s2 are k-similar (for some...

01 Oct 2022

Find Eventual Safe States Problem

LeetCode 802. There is a directed graph of n nodes...

01 Oct 2022

Cousins In Binary Tree Problem

LeetCode 993. Given the root of a binary tree with...

01 Oct 2022

Complete Binary Tree Inserter Problem

LeetCode 919. A complete binary tree is a binary tree...

30 Sep 2022

Check Completeness Of A Binary Tree Problem

LeetCode 958. Given the root of a binary tree, determine...

30 Sep 2022

Bus Routes Problem

LeetCode 815. You are given an array routes representing bus...

30 Sep 2022

All Nodes Distance K In Binary Tree Problem

LeetCode 863. Given the root of a binary tree, the...

30 Sep 2022

Swim In Rising Water Problem

LeetCode 778. You are given an n x n integer...

28 Sep 2022

Sliding Puzzle Problem

LeetCode 773. On an 2 x 3 board, there are...

28 Sep 2022

Redundant Connection Problem

LeetCode 684. In this problem, a tree is an undirected...

28 Sep 2022

Redundant Connection II Problem

LeetCode 685. In this problem, a rooted tree is a...

28 Sep 2022

Pyramid Transition Matrix Problem

LeetCode 756. You are stacking blocks to form a pyramid....

28 Sep 2022

Open The Lock Problem

LeetCode 752. You have a lock in front of you...

28 Sep 2022

Network Delay Time Problem

LeetCode 743. You are given a network of n nodes,...

28 Sep 2022

Two Sum IV - Input Is A BST Problem

LeetCode 653. Given the root of a Binary Search Tree...

27 Sep 2022

Print Binary Tree Problem

LeetCode 655. Given the root of a binary tree, construct...

27 Sep 2022

Minimum Distance Between BST Nodes Problem

LeetCode 783. Given the root of a Binary Search Tree...

27 Sep 2022

Merge Two Binary Trees Problem

LeetCode 617. You are given two binary trees root1 and...

27 Sep 2022

Maximum Width Of Binary Tree Problem

LeetCode 662. Given the root of a binary tree, return...

27 Sep 2022

Is Graph Bipartite? Problem

LeetCode 785. There is an undirected graph with n nodes,...

27 Sep 2022

Flood Fill Problem

LeetCode 733. An image is represented by an m x...

27 Sep 2022

Cut Off Trees For Golf Event Problem

LeetCode 675. You are asked to cut off all the...

27 Sep 2022

Max Area Of Island Problem

LeetCode 695. You are given an m x n binary...

26 Sep 2022

Employee Importance Problem

LeetCode 690. You have a data structure of employee information,...

26 Sep 2022

Couples Holding Hands Problem

LeetCode 765. There are n couples sitting in 2n seats...

26 Sep 2022

Contain Virus Problem

LeetCode 749. A virus is spreading rapidly, and your task...

26 Sep 2022

Cheapest Flights Within K Stops Problem

LeetCode 787. There are n cities connected by some number...

26 Sep 2022

Bulb Switcher II Problem

LeetCode 672. There is a room with n bulbs labeled...

26 Sep 2022

Average Of Levels In Binary Tree Problem

LeetCode 637. Given the root of a binary tree, return...

26 Sep 2022

All Paths From Source To Target Problem

LeetCode 797. Given a directed acyclic graph (DAG) of n...

26 Sep 2022

Add One Row To Tree Problem

LeetCode 623. Given the root of a binary tree and...

26 Sep 2022

Accounts Merge Problem

LeetCode 721. Given a list of accounts where each element...

26 Sep 2022

Zuma Game Problem

LeetCode 488. You are playing a variation of the game...

25 Sep 2022

Trapping Rain Water II Problem

LeetCode 407. Given an m x n integer matrix heightMap...

25 Sep 2022

Pacific Atlantic Water Flow Problem

LeetCode 417. There is an m x n rectangular island...

25 Sep 2022

Freedom Trail Problem

LeetCode 514. In the video game Fallout 4, the quest...

25 Sep 2022

Sum Of Left Leaves Problem

LeetCode 404. Given the root of a binary tree, return...

24 Sep 2022

Serialize And Deserialize BST Problem

LeetCode 449. Serialization is converting a data structure or object...

24 Sep 2022

Number Of Provinces Problem

LeetCode 547. There are n cities. Some of them are...

23 Sep 2022

N-Ary Tree Level Order Traversal Problem

LeetCode 429. Given an n-ary tree, return the level order...

23 Sep 2022

Minimum Genetic Mutation Problem

LeetCode 433. A gene string can be represented by an...

23 Sep 2022

Minimum Absolute Difference In BST Problem

LeetCode 530. Given the root of a Binary Search Tree...

22 Sep 2022

Minesweeper Problem

LeetCode 529. Let’s play the minesweeper game!

22 Sep 2022

Maximum Depth Of N-Ary Tree Problem

LeetCode 559. Given a n-ary tree, find its maximum depth....

22 Sep 2022

Island Perimeter Problem

LeetCode 463. You are given row x col grid representing...

22 Sep 2022

Find Largest Value In Each Tree Row Problem

LeetCode 515. Given the root of a binary tree, return...

21 Sep 2022

Find Bottom Left Tree Value Problem

LeetCode 513. Given the root of a binary tree, return...

21 Sep 2022

Water And Jug Problem Problem

LeetCode 365. You are given two jugs with capacities jug1Capacity...

19 Sep 2022

01 Matrix Problem

LeetCode 542. Given an m x n binary matrix mat,...

19 Sep 2022

Serialize And Deserialize Binary Tree Problem

LeetCode 297. Serialization is the process of converting a data...

18 Sep 2022

Remove Invalid Parentheses Problem

LeetCode 301. Given a string s that contains parentheses and...

18 Sep 2022

Perfect Squares Problem

LeetCode 279. Given an integer n, return the least number...

16 Sep 2022

Minimum Height Trees Problem

LeetCode 310. A tree is an undirected graph in which...

15 Sep 2022

Longest Increasing Path In A Matrix Problem

LeetCode 329. Given an m x n integers matrix, return...

10 Apr 2022

Invert Binary Tree Problem

LeetCode 226. Given the root of a binary tree, invert...

10 Apr 2022

Evaluate Division Problem

LeetCode 399. You are given an array of variable pairs...

10 Apr 2022

Course Schedule Problem

LeetCode 207. There are a total of numCourses courses you...

10 Apr 2022

Course Schedule II Problem

LeetCode 210. There are a total of numCourses courses you...

10 Apr 2022

Coin Change Problem

LeetCode 322. You are given an integer array coins representing...

10 Apr 2022

Binary Tree Right Side View Problem

LeetCode 199. Given the root of a binary tree, imagine...

04 Dec 2021

Clone Graph Problem

LeetCode 133. Given a reference of a node in a...

03 Dec 2021

Word Ladder Problem

LeetCode 127. Given two words, beginWord and endWord, and a...

29 Nov 2021

Word Ladder II Problem

LeetCode 126. Given two words, beginWord and endWord, and a...

29 Nov 2021

Surrounded Regions Problem

LeetCode 130. Given an m x n matrix board containing...

29 Nov 2021

Populating Next Right Pointers In Each Node Problem

LeetCode 116. You are given a perfect binary tree where...

29 Nov 2021

Populating Next Right Pointers In Each Node II Problem

LeetCode 117. Given a binary tree, populate each next pointer...

29 Nov 2021

Minimum Depth Of Binary Tree Problem

LeetCode 111. Given a binary tree, find its minimum depth....

29 Nov 2021

Symmetric Tree Problem

LeetCode 101. Given the root of a binary tree, check...

20 Nov 2021

Maximum Depth of Binary Tree Problem

LeetCode 104. Given the root of a binary tree, return...

20 Nov 2021

Construct Binary Tree From Inorder And Postorder Traversal Problem

LeetCode 106. Given two integer arrays inorder and postorder where...

20 Nov 2021

Binary Tree Zigzag Level Order Traversal Problem

LeetCode 103. Given the root of a binary tree, return...

20 Nov 2021

Binary Tree Level Order Traversal Problem

LeetCode 102. Given the root of a binary tree, return...

20 Nov 2021

Binary Tree Level Order Traversal II Problem

LeetCode 107. Given the root of a binary tree, return...

20 Nov 2021

Tag Binary Tree Leetcode

Convert Sorted Array to Binary Search Tree Problem

LeetCode 108. Given an integer array nums where the elements...

20 Nov 2021

Tag Union Find

Similar String Groups Problem

LeetCode 839. Two strings Xand Yare similar if we can...

01 Oct 2022

Satisfiability Of Equality Equations Problem

LeetCode 990. You are given an array of strings equations...

01 Oct 2022

Regions Cut By Slashes Problem

LeetCode 959. An n x n grid is composed of...

01 Oct 2022

Possible Bipartition Problem

LeetCode 886. We want to split a group of n...

01 Oct 2022

Most Stones Removed With Same Row Or Column Problem

LeetCode 947. On a 2D plane, we place n stones...

01 Oct 2022

Minimize Malware Spread Problem

LeetCode 924. You are given a network of n nodes...

01 Oct 2022

Minimize Malware Spread II Problem

LeetCode 928. You are given a network of n nodes...

01 Oct 2022

Making A Large Island Problem

LeetCode 827. You are given an n x n binary...

01 Oct 2022

Largest Component Size By Common Factor Problem

LeetCode 952. You are given an integer array of unique...

01 Oct 2022

Bricks Falling When Hit Problem

LeetCode 803. You are given an m x n binary...

30 Sep 2022

Swim In Rising Water Problem

LeetCode 778. You are given an n x n integer...

28 Sep 2022

Redundant Connection Problem

LeetCode 684. In this problem, a tree is an undirected...

28 Sep 2022

Redundant Connection II Problem

LeetCode 685. In this problem, a rooted tree is a...

28 Sep 2022

Is Graph Bipartite? Problem

LeetCode 785. There is an undirected graph with n nodes,...

27 Sep 2022

Max Area Of Island Problem

LeetCode 695. You are given an m x n binary...

26 Sep 2022

Couples Holding Hands Problem

LeetCode 765. There are n couples sitting in 2n seats...

26 Sep 2022

Accounts Merge Problem

LeetCode 721. Given a list of accounts where each element...

26 Sep 2022

Number Of Provinces Problem

LeetCode 547. There are n cities. Some of them are...

23 Sep 2022

Evaluate Division Problem

LeetCode 399. You are given an array of variable pairs...

10 Apr 2022

Surrounded Regions Problem

LeetCode 130. Given an m x n matrix board containing...

29 Nov 2021

Longest Consecutive Sequence Problem

LeetCode 128. Given an unsorted array of integers nums, return...

29 Nov 2021

Tag Graph

Sum Of Distances In Tree Problem

LeetCode 834. There is an undirected connected tree with n...

01 Oct 2022

Shortest Path Visiting All Nodes Problem

LeetCode 847. You have an undirected, connected graph of n...

01 Oct 2022

Satisfiability Of Equality Equations Problem

LeetCode 990. You are given an array of strings equations...

01 Oct 2022

Regions Cut By Slashes Problem

LeetCode 959. An n x n grid is composed of...

01 Oct 2022

Reachable Nodes In Subdivided Graph Problem

LeetCode 882. You are given an undirected graph (the “original...

01 Oct 2022

Possible Bipartition Problem

LeetCode 886. We want to split a group of n...

01 Oct 2022

Most Stones Removed With Same Row Or Column Problem

LeetCode 947. On a 2D plane, we place n stones...

01 Oct 2022

Loud And Rich Problem

LeetCode 851. There is a group of n people labeled...

01 Oct 2022

Keys And Rooms Problem

LeetCode 841. There are n rooms labeled from 0 to...

01 Oct 2022

Find The Town Judge Problem

LeetCode 997. In a town, there are n people labeled...

01 Oct 2022

Find Eventual Safe States Problem

LeetCode 802. There is a directed graph of n nodes...

01 Oct 2022

Cat And Mouse Problem

LeetCode 913. A game on an undirected graph is played...

30 Sep 2022

Redundant Connection Problem

LeetCode 684. In this problem, a tree is an undirected...

28 Sep 2022

Redundant Connection II Problem

LeetCode 685. In this problem, a rooted tree is a...

28 Sep 2022

Network Delay Time Problem

LeetCode 743. You are given a network of n nodes,...

28 Sep 2022

Is Graph Bipartite? Problem

LeetCode 785. There is an undirected graph with n nodes,...

27 Sep 2022

Cracking The Safe Problem

LeetCode 753. There is a safe protected by a password....

26 Sep 2022

Couples Holding Hands Problem

LeetCode 765. There are n couples sitting in 2n seats...

26 Sep 2022

Cheapest Flights Within K Stops Problem

LeetCode 787. There are n cities connected by some number...

26 Sep 2022

All Paths From Source To Target Problem

LeetCode 797. Given a directed acyclic graph (DAG) of n...

26 Sep 2022

Number Of Provinces Problem

LeetCode 547. There are n cities. Some of them are...

23 Sep 2022

Minimum Height Trees Problem

LeetCode 310. A tree is an undirected graph in which...

15 Sep 2022

Longest Increasing Path In A Matrix Problem

LeetCode 329. Given an m x n integers matrix, return...

10 Apr 2022

Evaluate Division Problem

LeetCode 399. You are given an array of variable pairs...

10 Apr 2022

Course Schedule Problem

LeetCode 207. There are a total of numCourses courses you...

10 Apr 2022

Course Schedule II Problem

LeetCode 210. There are a total of numCourses courses you...

10 Apr 2022

Clone Graph Problem

LeetCode 133. Given a reference of a node in a...

03 Dec 2021

Tag Design

Time Based Key-Value Store Problem

LeetCode 981. Design a time-based key-value data structure that can...

01 Oct 2022

Rle Iterator Problem

LeetCode 900. We can use run-length encoding (i.e., RLE) to...

01 Oct 2022

Online Stock Span Problem

LeetCode 901. Design an algorithm that collects daily price quotes...

01 Oct 2022

Online Election Problem

LeetCode 911. You are given two integer arrays persons and...

01 Oct 2022

Number Of Recent Calls Problem

LeetCode 933. You have a RecentCounter class which counts the...

01 Oct 2022

Maximum Frequency Stack Problem

LeetCode 895. Design a stack-like data structure to push elements...

01 Oct 2022

Exam Room Problem

LeetCode 855. There is an exam room with n seats...

01 Oct 2022

Complete Binary Tree Inserter Problem

LeetCode 919. A complete binary tree is a binary tree...

30 Sep 2022

Range Module Problem

LeetCode 715. A Range Module is a module that tracks...

28 Sep 2022

My Calendar III Problem

LeetCode 732. A k-booking happens when k events have some...

28 Sep 2022

My Calendar II Problem

LeetCode 731. You are implementing a program to use as...

28 Sep 2022

My Calendar I Problem

LeetCode 729. You are implementing a program to use as...

28 Sep 2022

Prefix And Suffix Search Problem

LeetCode 745. Design a special dictionary with some words that...

27 Sep 2022

Design Circular Queue Problem

LeetCode 622. Design your implementation of the circular queue. The...

27 Sep 2022

Design Circular Deque Problem

LeetCode 641. Design your implementation of the circular double-ended queue...

27 Sep 2022

Map Sum Pairs Problem

LeetCode 677. Design a map that allows you to do...

26 Sep 2022

Kth Largest Element In A Stream Problem

LeetCode 703. Design a class to find the k^th largest...

26 Sep 2022

Implement Magic Dictionary Problem

LeetCode 676. Design a data structure that is initialized with...

26 Sep 2022

Design Linked List Problem

LeetCode 707. Design your implementation of the linked list. You...

26 Sep 2022

Design Hashset Problem

LeetCode 705. Design a HashSet without using any built-in hash...

26 Sep 2022

Design Hashmap Problem

LeetCode 706. Design a HashMap without using any built-in hash...

26 Sep 2022

Serialize And Deserialize BST Problem

LeetCode 449. Serialization is converting a data structure or object...

24 Sep 2022

LFU Cache Problem

LeetCode 460. Design and implement a data structure for a...

22 Sep 2022

Encode And Decode TinyURL Problem

LeetCode 535. TinyURL is a URL shortening service where you...

21 Sep 2022

All O'One Data Structure Problem

LeetCode 432. Design a data structure to store the strings...

19 Sep 2022

Serialize And Deserialize Binary Tree Problem

LeetCode 297. Serialization is the process of converting a data...

18 Sep 2022

Range Sum Query - Immutable Problem

LeetCode 303. Given an integer array nums, handle multiple queries...

16 Sep 2022

Range Sum Query 2D - Immutable Problem

LeetCode 304. Given a 2D matrix matrix, handle multiple queries...

16 Sep 2022

Peeking Iterator Problem

LeetCode 284. Design an iterator that supports the peek operation...

16 Sep 2022

Insert Delete Getrandom O(1) - Duplicates Allowed Problem

LeetCode 381. RandomizedCollection is a data structure that contains a...

10 Apr 2022

Implement Stack Using Queues Problem

LeetCode 225. Implement a last-in-first-out (LIFO) stack using only two...

10 Apr 2022

Implement Queue Using Stacks Problem

LeetCode 232. Implement a first in first out (FIFO) queue...

10 Apr 2022

Flatten Nested List Iterator Problem

LeetCode 341. You are given a nested list of integers...

10 Apr 2022

Find Median From Data Stream Problem

LeetCode 295. The median is the middle value in an...

10 Apr 2022

Design Twitter Problem

LeetCode 355. Design a simplified version of Twitter where users...

10 Apr 2022

Design Add And Search Words Data Structure Problem

LeetCode 211. Design a data structure that supports adding new...

10 Apr 2022

Data Stream As Disjoint Intervals Problem

LeetCode 352. Given a data stream input of non-negative integers...

10 Apr 2022

Min Stack Problem

LeetCode 155. Design a stack that supports push, pop, top,...

04 Dec 2021

Binary Search Tree Iterator Problem

LeetCode 173. Implement the BSTIterator class that represents an iterator...

04 Dec 2021

Lru Cache Problem

LeetCode 146. Design a data structure that follows the constraints...

03 Dec 2021

Tag Doubly-Linked List

LFU Cache Problem

LeetCode 460. Design and implement a data structure for a...

22 Sep 2022

Flatten A Multilevel Doubly Linked List Problem

LeetCode 430. You are given a doubly linked list, which...

21 Sep 2022

All O'One Data Structure Problem

LeetCode 432. Design a data structure to store the strings...

19 Sep 2022

Lru Cache Problem

LeetCode 146. Design a data structure that follows the constraints...

03 Dec 2021

Tag Geometry

Surface Area Of 3D Shapes Problem

LeetCode 892. You are given an n x n grid...

01 Oct 2022

Rectangle Overlap Problem

LeetCode 836. An axis-aligned rectangle is represented as a list...

01 Oct 2022

Projection Area Of 3D Shapes Problem

LeetCode 883. You are given an n x n grid...

01 Oct 2022

Mirror Reflection Problem

LeetCode 858. There is a special square room with mirrors...

01 Oct 2022

Minimum Area Rectangle Problem

LeetCode 939. You are given an array of points in...

01 Oct 2022

Minimum Area Rectangle II Problem

LeetCode 963. You are given an array of points in...

01 Oct 2022

Largest Triangle Area Problem

LeetCode 812. Given an array of points on the X-Y...

01 Oct 2022

K Closest Points To Origin Problem

LeetCode 973. Given an array of points where points[i] =...

01 Oct 2022

Erect The Fence Problem

LeetCode 587. You are given an array trees where trees[i]...

25 Sep 2022

Valid Square Problem

LeetCode 593. Given the coordinates of four points in 2D...

24 Sep 2022

Generate Random Point In A Circle Problem

LeetCode 478. Given the radius and the position of the...

22 Sep 2022

Self Crossing Problem

LeetCode 335. You are given an array of integers distance....

18 Sep 2022

Rectangle Area Problem

LeetCode 223. Given the coordinates of two rectilinear rectangles in...

18 Sep 2022

Max Points On A Line Problem

LeetCode 149. Given an array of points where points[i] =...

03 Dec 2021

Tag Merge Sort

Sort An Array Problem

LeetCode 912. Given an array of integers nums, sort the...

01 Oct 2022

Reverse Pairs Problem

LeetCode 493. Given an integer array nums, return the number...

24 Sep 2022

Count Of Smaller Numbers After Self Problem

LeetCode 315. You are given an integer array nums and...

10 Apr 2022

Count Of Range Sum Problem

LeetCode 327. Given an integer array nums and two integers...

10 Apr 2022

Sort List Problem

LeetCode 148. Given the head of a linked list, return...

03 Dec 2021

Tag Memoization

All Possible Full Binary Trees Problem

LeetCode 894. Given an integer n, return a list of...

30 Sep 2022

Shopping Offers Problem

LeetCode 638. In LeetCode Store, there are n items to...

28 Sep 2022

Partition To K Equal Sum Subsets Problem

LeetCode 698. Given an integer array nums and an integer...

27 Sep 2022

Zuma Game Problem

LeetCode 488. You are playing a variation of the game...

25 Sep 2022

Remove Boxes Problem

LeetCode 546. You are given several boxes with different colors...

24 Sep 2022

Fibonacci Number Problem

LeetCode 509. The Fibonacci numbers, commonly denoted F(n) form a...

21 Sep 2022

Longest Increasing Path In A Matrix Problem

LeetCode 329. Given an m x n integers matrix, return...

10 Apr 2022

Integer Replacement Problem

LeetCode 397. Given a positive integer n,you can apply one...

10 Apr 2022

Different Ways To Add Parentheses Problem

LeetCode 241. Given a string expression of numbers and operators,...

10 Apr 2022

Word Break Problem

LeetCode 139. Given a string s and a dictionary of...

03 Dec 2021

Word Break II Problem

LeetCode 140. Given a string s and a dictionary of...

03 Dec 2021

Tag Iterator

Rle Iterator Problem

LeetCode 900. We can use run-length encoding (i.e., RLE) to...

01 Oct 2022

Peeking Iterator Problem

LeetCode 284. Design an iterator that supports the peek operation...

16 Sep 2022

Flatten Nested List Iterator Problem

LeetCode 341. You are given a nested list of integers...

10 Apr 2022

Binary Search Tree Iterator Problem

LeetCode 173. Implement the BSTIterator class that represents an iterator...

04 Dec 2021

Tag Counting

Subdomain Visit Count Problem

LeetCode 811. A website domain “discuss.leetcode.com” consists of various subdomains....

01 Oct 2022

Subarrays With K Different Integers Problem

LeetCode 992. Given an integer array nums and an integer...

01 Oct 2022

Rle Iterator Problem

LeetCode 900. We can use run-length encoding (i.e., RLE) to...

01 Oct 2022

Reordered Power Of 2 Problem

LeetCode 869. You are given an integer n. We reorder...

01 Oct 2022

Most Common Word Problem

LeetCode 819. Given a string paragraph and a string array...

01 Oct 2022

Minimum Increment To Make Array Unique Problem

LeetCode 945. You are given an integer array nums. In...

01 Oct 2022

Ransom Note Problem

LeetCode 383. Given two stings ransomNote and magazine, return true...

16 Sep 2022

Majority Element II Problem

LeetCode 229. Given an integer array of size n, find...

10 Apr 2022

First Unique Character In A String Problem

LeetCode 387. Given a string s, find the first non-repeating...

10 Apr 2022

Bulls And Cows Problem

LeetCode 299. You are playing the Bulls and Cows game...

10 Apr 2022

Majority Element Problem

LeetCode 169. Given an array nums of size n, return...

04 Dec 2021

Tag Bucket Sort

Contains Duplicate III Problem

LeetCode 220. Given an integer array nums and two integers...

10 Apr 2022

Maximum Gap Problem

LeetCode 164. Given an integer array nums, return the maximum...

04 Dec 2021

Tag Radix Sort

Maximum Gap Problem

LeetCode 164. Given an integer array nums, return the maximum...

04 Dec 2021

Tag Rolling Hash

Shortest Palindrome Problem

LeetCode 214. You are given a string s. You can...

18 Sep 2022

Repeated DNA Sequences Problem

LeetCode 187. The DNA sequence is composed of a series...

04 Dec 2021

Tag Hash Function

Design Hashset Problem

LeetCode 705. Design a HashSet without using any built-in hash...

26 Sep 2022

Design Hashmap Problem

LeetCode 706. Design a HashMap without using any built-in hash...

26 Sep 2022

Encode And Decode TinyURL Problem

LeetCode 535. TinyURL is a URL shortening service where you...

21 Sep 2022

Shortest Palindrome Problem

LeetCode 214. You are given a string s. You can...

18 Sep 2022

Repeated DNA Sequences Problem

LeetCode 187. The DNA sequence is composed of a series...

04 Dec 2021

Tag Brainteaser

Nim Game Problem

LeetCode 292. You are playing the following Nim Game with...

15 Sep 2022

Bulb Switcher Problem

LeetCode 319. There are n bulbs that are initially off....

10 Apr 2022

Tag Ordered Set

Range Module Problem

LeetCode 715. A Range Module is a module that tracks...

28 Sep 2022

Falling Squares Problem

LeetCode 699. There are several squares being dropped onto the...

27 Sep 2022

Random Point In Non-Overlapping Rectangles Problem

LeetCode 497. You are given an array of non-overlapping axis-aligned...

25 Sep 2022

132 Pattern Problem

LeetCode 456. Given an arrayof n integers nums, a 132...

19 Sep 2022

Data Stream As Disjoint Intervals Problem

LeetCode 352. Given a data stream input of non-negative integers...

10 Apr 2022

Count Of Smaller Numbers After Self Problem

LeetCode 315. You are given an integer array nums and...

10 Apr 2022

Count Of Range Sum Problem

LeetCode 327. Given an integer array nums and two integers...

10 Apr 2022

Contains Duplicate III Problem

LeetCode 220. Given an integer array nums and two integers...

10 Apr 2022

Tag Binary Indexed Tree

Number Of Longest Increasing Subsequence Problem

LeetCode 673. Given an integer arraynums, return the number of...

27 Sep 2022

Queue Reconstruction By Height Problem

LeetCode 406. You are given an array of people, people,...

24 Sep 2022

Count Of Smaller Numbers After Self Problem

LeetCode 315. You are given an integer array nums and...

10 Apr 2022

Count Of Range Sum Problem

LeetCode 327. Given an integer array nums and two integers...

10 Apr 2022

Tag Segment Tree

Rectangle Area II Problem

LeetCode 850. You are given a 2D array of axis-aligned...

01 Oct 2022

Range Module Problem

LeetCode 715. A Range Module is a module that tracks...

28 Sep 2022

My Calendar III Problem

LeetCode 732. A k-booking happens when k events have some...

28 Sep 2022

My Calendar II Problem

LeetCode 731. You are implementing a program to use as...

28 Sep 2022

My Calendar I Problem

LeetCode 729. You are implementing a program to use as...

28 Sep 2022

Number Of Longest Increasing Subsequence Problem

LeetCode 673. Given an integer arraynums, return the number of...

27 Sep 2022

Falling Squares Problem

LeetCode 699. There are several squares being dropped onto the...

27 Sep 2022

Queue Reconstruction By Height Problem

LeetCode 406. You are given an array of people, people,...

24 Sep 2022

Count Of Smaller Numbers After Self Problem

LeetCode 315. You are given an integer array nums and...

10 Apr 2022

Count Of Range Sum Problem

LeetCode 327. Given an integer array nums and two integers...

10 Apr 2022

Tag Enumeration

Consecutive Numbers Sum Problem

LeetCode 829. Given an integer n, return the number of...

30 Sep 2022

Count Primes Problem

LeetCode 204. Given an integer n, return the number of...

10 Apr 2022

Tag Number Theory

Count Primes Problem

LeetCode 204. Given an integer n, return the number of...

10 Apr 2022

Tag Topological Sort

Loud And Rich Problem

LeetCode 851. There is a group of n people labeled...

01 Oct 2022

Cat And Mouse Problem

LeetCode 913. A game on an undirected graph is played...

30 Sep 2022

Minimum Height Trees Problem

LeetCode 310. A tree is an undirected graph in which...

15 Sep 2022

Longest Increasing Path In A Matrix Problem

LeetCode 329. Given an m x n integers matrix, return...

10 Apr 2022

Course Schedule Problem

LeetCode 207. There are a total of numCourses courses you...

10 Apr 2022

Course Schedule II Problem

LeetCode 210. There are a total of numCourses courses you...

10 Apr 2022

Tag Monotonic Stack

Online Stock Span Problem

LeetCode 901. Design an algorithm that collects daily price quotes...

01 Oct 2022

Odd Even Jump Problem

LeetCode 975. You are given an integer array arr. From...

01 Oct 2022

Maximum Width Ramp Problem

LeetCode 962. A ramp in an integer array nums is...

01 Oct 2022

Car Fleet Problem

LeetCode 853. There are n cars going to the same...

30 Sep 2022

Max Chunks To Make Sorted Problem

LeetCode 769. You are given an integer array arr of...

27 Sep 2022

Max Chunks To Make Sorted II Problem

LeetCode 768. You are given an integer array arr.

27 Sep 2022

Maximum Binary Tree Problem

LeetCode 654. You are given an integer array nums with...

26 Sep 2022

Daily Temperatures Problem

LeetCode 739. Given an array of integers temperatures represents the...

26 Sep 2022

Shortest Unsorted Continuous Subarray Problem

LeetCode 581. Given an integer array nums, you need to...

24 Sep 2022

Remove K Digits Problem

LeetCode 402. Given string num representing a non-negative integer num,...

24 Sep 2022

Next Greater Element II Problem

LeetCode 503. Given a circular integer array nums (i.e., the...

23 Sep 2022

Next Greater Element I Problem

LeetCode 496. The next greater element of some element x...

23 Sep 2022

132 Pattern Problem

LeetCode 456. Given an arrayof n integers nums, a 132...

19 Sep 2022

Remove Duplicate Letters Problem

LeetCode 316. Given a string s, remove duplicate letters so...

18 Sep 2022

Create Maximum Number Problem

LeetCode 321. You are given two integer arrays nums1 and...

10 Apr 2022

Tag Heap

Sort An Array Problem

LeetCode 912. Given an array of integers nums, sort the...

01 Oct 2022

Shortest Subarray With Sum At Least K Problem

LeetCode 862. Given an integer array nums and an integer...

01 Oct 2022

Reachable Nodes In Subdivided Graph Problem

LeetCode 882. You are given an undirected graph (the “original...

01 Oct 2022

Minimum Number Of Refueling Stops Problem

LeetCode 871. A car travels from a starting position to...

01 Oct 2022

Minimum Cost To Hire K Workers Problem

LeetCode 857. There are n workers. You are given two...

01 Oct 2022

K Closest Points To Origin Problem

LeetCode 973. Given an array of points where points[i] =...

01 Oct 2022

Top K Frequent Words Problem

LeetCode 692. Given an array of strings words and an...

28 Sep 2022

Task Scheduler Problem

LeetCode 621. Given a characters array tasks, representing the tasks...

28 Sep 2022

Swim In Rising Water Problem

LeetCode 778. You are given an n x n integer...

28 Sep 2022

Reorganize String Problem

LeetCode 767. Given a string s, rearrange the characters of...

28 Sep 2022

Network Delay Time Problem

LeetCode 743. You are given a network of n nodes,...

28 Sep 2022

Split Array Into Consecutive Subsequences Problem

LeetCode 659. You are given an integer array nums that...

27 Sep 2022

Smallest Range Covering Elements From K Lists Problem

LeetCode 632. You have k lists of sorted integers in...

27 Sep 2022

Cut Off Trees For Golf Event Problem

LeetCode 675. You are asked to cut off all the...

27 Sep 2022

Kth Largest Element In A Stream Problem

LeetCode 703. Design a class to find the k^th largest...

26 Sep 2022

K-Th Smallest Prime Fraction Problem

LeetCode 786. You are given a sorted integer array arr...

26 Sep 2022

Find K Closest Elements Problem

LeetCode 658. Given a sorted integer array arr, two integers...

26 Sep 2022

Course Schedule III Problem

LeetCode 630. There are n different online courses numbered from...

26 Sep 2022

Cheapest Flights Within K Stops Problem

LeetCode 787. There are n cities connected by some number...

26 Sep 2022

Trapping Rain Water II Problem

LeetCode 407. Given an m x n integer matrix heightMap...

25 Sep 2022

Strong Password Checker Problem

LeetCode 420. A password is considered strong if the below...

25 Sep 2022

IPO Problem

LeetCode 502. Suppose LeetCode will start its IPO soon. In...

25 Sep 2022

Sort Characters By Frequency Problem

LeetCode 451. Given a string s, sort it in decreasing...

24 Sep 2022

Sliding Window Median Problem

LeetCode 480. The median is the middle value in an...

24 Sep 2022

Relative Ranks Problem

LeetCode 506. You are given an integer array score of...

24 Sep 2022

Ugly Number II Problem

LeetCode 264. An ugly number is a positive integer whose...

18 Sep 2022

Top K Frequent Elements Problem

LeetCode 347. Given an integer array nums and an integer...

18 Sep 2022

Super Ugly Number Problem

LeetCode 313. A super ugly number is a positive integer...

18 Sep 2022

Sliding Window Maximum Problem

LeetCode 239. You are given an array of integersnums, there...

18 Sep 2022

Kth Smallest Element In A Sorted Matrix Problem

LeetCode 378. Given an n x n matrix where each...

10 Apr 2022

Kth Largest Element In An Array Problem

LeetCode 215. Given an integer array nums and an integer...

10 Apr 2022

Find Median From Data Stream Problem

LeetCode 295. The median is the middle value in an...

10 Apr 2022

Find K Pairs With Smallest Sums Problem

LeetCode 373. You are given two integer arrays nums1 and...

10 Apr 2022

Design Twitter Problem

LeetCode 355. Design a simplified version of Twitter where users...

10 Apr 2022

Tag Shortest Path

Reachable Nodes In Subdivided Graph Problem

LeetCode 882. You are given an undirected graph (the “original...

01 Oct 2022

Network Delay Time Problem

LeetCode 743. You are given a network of n nodes,...

28 Sep 2022

Cheapest Flights Within K Stops Problem

LeetCode 787. There are n cities connected by some number...

26 Sep 2022

Evaluate Division Problem

LeetCode 399. You are given an array of variable pairs...

10 Apr 2022

Tag Data Stream

Online Stock Span Problem

LeetCode 901. Design an algorithm that collects daily price quotes...

01 Oct 2022

Number Of Recent Calls Problem

LeetCode 933. You have a RecentCounter class which counts the...

01 Oct 2022

Kth Largest Element In A Stream Problem

LeetCode 703. Design a class to find the k^th largest...

26 Sep 2022

Find Median From Data Stream Problem

LeetCode 295. The median is the middle value in an...

10 Apr 2022

Tag Interactive

Guess Number Higher Or Lower Problem

LeetCode 374. We are playing the Guess Game. The game...

10 Apr 2022

First Bad Version Problem

LeetCode 278. You are a product manager and currently leading...

10 Apr 2022

Tag Simulation

Walking Robot Simulation Problem

LeetCode 874. A robot on an infinite XY-plane starts at...

01 Oct 2022

Backspace String Compare Problem

LeetCode 844. Given two strings s and t, return true...

30 Sep 2022

Available Captures For Rook Problem

LeetCode 999. On an 8 x 8 chessboard, there is...

30 Sep 2022

Solve The Equation Problem

LeetCode 640. Solve a given equation and return the value...

28 Sep 2022

Baseball Game Problem

LeetCode 682. You are keeping score for a baseball game...

26 Sep 2022

Teemo Attacking Problem

LeetCode 495. Our hero Teemo is attacking an enemy Ashe...

25 Sep 2022

Reshape The Matrix Problem

LeetCode 566. In MATLAB, there is a handy function called...

24 Sep 2022

Fraction Addition And Subtraction Problem

LeetCode 592. Given a string expression representing an expression of...

21 Sep 2022

Diagonal Traverse Problem

LeetCode 498. Given an m x n matrix mat, return...

21 Sep 2022

Complex Number Multiplication Problem

LeetCode 537. A complex number can be represented as a...

21 Sep 2022

Fizz Buzz Problem

LeetCode 412. Given an integer n, return a string array...

19 Sep 2022

Add Strings Problem

LeetCode 415. Given two non-negative integers, num1 and num2 represented...

19 Sep 2022

Game Of Life Problem

LeetCode 289. The Game of Life, also known simply as...

10 Apr 2022

Tag Game Theory

Nim Game Problem

LeetCode 292. You are playing the following Nim Game with...

15 Sep 2022

Guess Number Higher Or Lower II Problem

LeetCode 375. We are playing the Guessing Game. The game...

10 Apr 2022

Tag Counting Sort

Array Partition I Problem

LeetCode 561. Given an integer array nums of 2n integers,...

19 Sep 2022

H-Index Problem

LeetCode 274. Given an array of integers citations where citations[i]...

10 Apr 2022

Tag Randomized

Random Pick With Blacklist Problem

LeetCode 710. You are given an integer n and an...

28 Sep 2022

Random Point In Non-Overlapping Rectangles Problem

LeetCode 497. You are given an array of non-overlapping axis-aligned...

25 Sep 2022

Random Pick With Weight Problem

LeetCode 528. You are given a 0-indexed array of positive...

24 Sep 2022

Random Flip Matrix Problem

LeetCode 519. There is an m x n binary grid...

24 Sep 2022

Implement Rand10() Using Rand7() Problem

LeetCode 470. Given the API rand7() that generates a uniform...

22 Sep 2022

Generate Random Point In A Circle Problem

LeetCode 478. Given the radius and the position of the...

22 Sep 2022

Shuffle An Array Problem

LeetCode 384. Given an integer array nums, design an algorithm...

18 Sep 2022

Random Pick Index Problem

LeetCode 398. Given an integer array nums with possible duplicates,...

16 Sep 2022

Linked List Random Node Problem

LeetCode 382. Given a singly linked list, return a random...

10 Apr 2022

Insert Delete Getrandom O(1) - Duplicates Allowed Problem

LeetCode 381. RandomizedCollection is a data structure that contains a...

10 Apr 2022

Tag Quickselect

Kth Largest Element In An Array Problem

LeetCode 215. Given an integer array nums and an integer...

10 Apr 2022

Tag Reservoir Sampling

Random Pick Index Problem

LeetCode 398. Given an integer array nums with possible duplicates,...

16 Sep 2022

Linked List Random Node Problem

LeetCode 382. Given a singly linked list, return a random...

10 Apr 2022

Tag Prefix Sum

Minimum Number Of K Consecutive Bit Flips Problem

LeetCode 995. You are given a binary array nums and...

01 Oct 2022

Binary Subarrays With Sum Problem

LeetCode 930. Given a binary array nums and an integer...

30 Sep 2022

Find Pivot Index Problem

LeetCode 724. Given an array of integers nums, calculate the...

28 Sep 2022

Smallest Rotation With Highest Score Problem

LeetCode 798. You are given an array nums. You can...

27 Sep 2022

Random Point In Non-Overlapping Rectangles Problem

LeetCode 497. You are given an array of non-overlapping axis-aligned...

25 Sep 2022

Random Pick With Weight Problem

LeetCode 528. You are given a 0-indexed array of positive...

24 Sep 2022

Contiguous Array Problem

LeetCode 525. Given a binary array nums, return the maximum...

21 Sep 2022

Range Sum Query - Immutable Problem

LeetCode 303. Given an integer array nums, handle multiple queries...

16 Sep 2022

Range Sum Query 2D - Immutable Problem

LeetCode 304. Given a 2D matrix matrix, handle multiple queries...

16 Sep 2022

Product Of Array Except Self Problem

LeetCode 238. Given an integer array nums, return an array...

16 Sep 2022

Minimum Size Subarray Sum Problem

LeetCode 209. Given an array of positive integers nums and...

15 Sep 2022

Tag Line Sweep

Rectangle Area II Problem

LeetCode 850. You are given a 2D array of axis-aligned...

01 Oct 2022

Perfect Rectangle Problem

LeetCode 391. Given an array rectangles where rectangles[i] = [x_i,...

16 Sep 2022

Tag String Matching

Repeated Substring Pattern Problem

LeetCode 459. Given a string s, check if it can...

24 Sep 2022

Shortest Palindrome Problem

LeetCode 214. You are given a string s. You can...

18 Sep 2022

Tag Monotonic Queue

Sliding Window Maximum Problem

LeetCode 239. You are given an array of integersnums, there...

18 Sep 2022

Tag Dyanmic Programming

Super Ugly Number Problem

LeetCode 313. A super ugly number is a positive integer...

18 Sep 2022

Tag Rejection Sampling

Implement Rand10() Using Rand7() Problem

LeetCode 470. Given the API rand7() that generates a uniform...

22 Sep 2022

Generate Random Point In A Circle Problem

LeetCode 478. Given the radius and the position of the...

22 Sep 2022

Tag Probability and Statistics

Implement Rand10() Using Rand7() Problem

LeetCode 470. Given the API rand7() that generates a uniform...

22 Sep 2022

Tag Bitmask

Split Array With Same Average Problem

LeetCode 805. You are given an integer array nums.

01 Oct 2022

Shortest Path Visiting All Nodes Problem

LeetCode 847. You have an undirected, connected graph of n...

01 Oct 2022

Find The Shortest Superstring Problem

LeetCode 943. Given an array of strings words, return the...

01 Oct 2022

Stickers To Spell Word Problem

LeetCode 691. We are given n different types of stickers....

28 Sep 2022

Shopping Offers Problem

LeetCode 638. In LeetCode Store, there are n items to...

28 Sep 2022

Partition To K Equal Sum Subsets Problem

LeetCode 698. Given an integer array nums and an integer...

27 Sep 2022

Matchsticks To Square Problem

LeetCode 473. You are given an integer array matchsticks where...

22 Sep 2022