LeetCode Solution List

This is a growing list of LeetCode problems and solutions. All problems and solutions are listed under different categories.

Algorithm And Data Structure

No.   Problem   Difficulty   Solution
1   Two Sum   `Easy`   Link
2   Add Two Numbers   `Medium`   Link
3   Longest Substring Without Repeating Characters   `Medium`   Link
4   Median Of Two Sorted Arrays   `Hard`   Link
5   Longest Palindromic Substring   `Medium`   Link
6   Zigzag Conversion   `Medium`   Link
7   Reverse Integer   `Medium`   Link
8   String To Integer (atoi)   `Medium`   Link
9   Palindrome Number   `Easy`   Link
10   Regular Expression Matching   `Hard`   Link
11   Container With Most Water   `Medium`   Link
12   Integer To Roman   `Medium`   Link
13   Roman To Integer   `Easy`   Link
14   Longest Common Prefix   `Easy`   Link
15   Three Sum   `Medium`   Link
16   3Sum Closest   `Medium`   Link
17   Letter Combinations Of A Phone Number   `Medium`   Link
18   Four Sum   `Medium`   Link
19   Remove Nth Node From End Of List   `Medium`   Link
20   Valid Parentheses   `Easy`   Link
21   Merge Two Sorted Lists   `Easy`   Link
22   Generate Parentheses   `Medium`   Link
23   Merge K Sorted Lists   `Hard`   Link
24   Swap Nodes In Pairs   `Medium`   Link
25   Reverse Nodes In K-Group   `Hard`   Link
26   Remove Duplicates From Sorted Array   `Easy`   Link
27   Remove Element   `Easy`   Link
28   Implement strStr()   `Easy`   Link
29   Divide Two Integers   `Medium`   Link
30   Substring with Concatenation of All Words   `Hard`   Link
31   Next Permutation   `Medium`   Link
32   Longest Valid Parentheses   `Hard`   Link
33   Search in Rotated Sorted Array   `Medium`   Link
34   Find First and Last Position of Element in Sorted Array   `Medium`   Link
35   Search Insert Position   `Easy`   Link
36   Valid Sudoku   `Medium`   Link
37   Sudoku Solver   `Hard`   Link
38   Count And Say   `Medium`   Link
39   Combination Sum   `Medium`   Link
40   Combination Sum II   `Medium`   Link
41   First Missing Positive   `Hard`   Link
42   Trapping Rain Water   `Hard`   Link
43   Multiply Strings   `Medium`   Link
44   Wildcard Matching   `Hard`   Link
45   Jump Game II   `Medium`   Link
46   Permutations   `Medium`   Link
47   Permutations II   `Medium`   Link
48   Rotate Image   `Medium`   Link
49   Group Anagrams   `Medium`   Link
50   Pow(x,n)   `Medium`   Link
51   N-Queens   `Hard`   Link
52   N-Queens II   `Hard`   Link
53   Maximum Subarray   `Easy`   Link
54   Spiral Matrix   `Medium`   Link
55   Jump Game   `Medium`   Link
56   Merge Intervals   `Medium`   Link
57   Insert Interval   `Medium`   Link
58   Length Of Last Word   `Easy`   Link
59   Spiral Matrix II   `Medium`   Link
60   Permutation Sequence   `Hard`   Link
61   Rotate List   `Medium`   Link
62   Unique Paths   `Medium`   Link
63   Unique Paths II   `Medium`   Link
64   Minimum Path Sum   `Medium`   Link
65   Valid Number   `Hard`   Link
66   Plus One   `Easy`   Link
67   Add Binary   `Easy`   Link
68   Text Justification   `Hard`   Link
69   Sqrt(x)   `Easy`   Link
70   Climbing Stairs   `Easy`   Link
71   Simplify Path   `Medium`   Link
72   Edit Distance   `Hard`   Link
73   Set Matrix Zeroes   `Medium`   Link
74   Search A 2D Matrix   `Medium`   Link
75   Sort Colors   `Medium`   Link
76   Minimum Window Substring   `Hard`   Link
77   Combinations   `Medium`   Link
78   Subsets   `Medium`   Link
79   Word Search   `Medium`   Link
80   Remove Duplicates From Sorted Array II   `Medium`   Link
81   Search In Rotated Sorted Array II   `Medium`   Link
82   Remove Duplicates From Sorted List II   `Medium`   Link
83   Remove Duplicates From Sorted List   `Easy`   Link
84   Largest Rectangle In Histogram   `Hard`   Link
85   Maximal Rectangle   `Hard`   Link
86   Partition List   `Medium`   Link
87   Scramble String   `Hard`   Link
88   Merge Sorted Array   `Easy`   Link
89   Gray Code   `Medium`   Link
90   Subsets II   `Medium`   Link
91   Decode Ways   `Medium`   Link
92   Reverse Linked List II   `Medium`   Link
93   Restore IP Addresses   `Medium`   Link
94   Binary Tree Inorder Traversal   `Easy`   Link
95   Unique Binary Search Trees II   `Medium`   Link
96   Unique Binary Search Trees   `Medium`   Link
97   Interleaving String   `Medium`   Link
98   Validate Binary Search Tree   `Medium`   Link
99   Recover Binary Search Tree   `Medium`   Link
100   Same Tree   `Easy`   Link
101   Symmetric Tree   `Easy`   Link
102   Binary Tree Level Order Traversal   `Medium`   Link
103   Binary Tree Zigzag Level Order Traversal   `Medium`   Link
104   Maximum Depth Of Binary Tree   `Easy`   Link
105   Construct Binary Tree From Preorder And Inorder Traversal   `Medium`   Link
106   Construct Binary Tree From Inorder And Postorder Traversal   `Medium`   Link
107   Binary Tree Level Order Traversal II   `Medium`   Link
108   Convert Sorted Array To Binary Search Tree   `Easy`   Link
109   Convert Sorted List To Binary Search Tree   `Medium`   Link
110   Balanced Binary Tree   `Easy`   Link
111   Minimum Depth Of Binary Tree   `Easy`   Link
112   Path Sum   `Easy`   Link
113   Path Sum II   `Medium`   Link
114   Flatten Binary Tree To Linked List   `Medium`   Link
115   Distinct Subsequences   `Hard`   Link
116   Populating Next Right Pointers In Each Node   `Medium`   Link
117   Populating Next Right Pointers In Each Node II   `Medium`   Link
118   Pascal’s Triangle   `Easy`   Link
119   Pascal’s Triangle II   `Easy`   Link
120   Triangle   `Medium`   Link
121   Best Time To Buy And Sell Stock   `Easy`   Link
122   Best Time To Buy And Sell Stock II   `Medium`   Link
123   Best Time To Buy And Sell Stock III   `Hard`   Link
124   Binary Tree Maximum Path Sum   `Hard`   Link
125   Valid Palindrome   `Easy`   Link
126   Word Ladder II   `Hard`   Link
127   Word Ladder   `Hard`   Link
128   Longest Consecutive Sequence   `Medium`   Link
129   Sum Root To Leaf Numbers   `Medium`   Link
130   Surrounded Regions   `Medium`   Link
131   Palindrome Partitioning   `Medium`   Link
132   Palindrome Partitioning II   `Hard`   Link
133   Clone Graph   `Medium`   Link
134   Gas Station   `Medium`   Link
135   Candy   `Hard`   Link
136   Single Number   `Easy`   Link
137   Single Number II   `Medium`   Link
138   Copy List With Random Pointer   `Medium`   Link
139   Word Break   `Medium`   Link
140   Word Break II   `Hard`   Link
141   Linked List Cycle   `Easy`   Link
142   Linked List Cycle II   `Medium`   Link
143   Reorder List   `Medium`   Link
144   Binary Tree Preorder Traversal   `Easy`   Link
145   Binary Tree Postorder Traversal   `Easy`   Link
146   LRU Cache   `Medium`   Link
147   Insertion Sort List   `Medium`   Link
148   Sort List   `Medium`   Link
149   Max Points On A Line   `Hard`   Link
150   Evaluate Reverse Polish Notation   `Medium`   Link
151   Reverse Words In A String   `Medium`   Link
152   Maximum Product Subarray   `Medium`   Link
153   Find Minimum In Rotated Sorted Array   `Medium`   Link
154   Find Minimum In Rotated Sorted Array II   `Hard`   Link
155   Min Stack   `Easy`   Link
160   Intersection Of Two Linked Lists   `Easy`   Link
162   Find Peak Element   `Medium`   Link
164   Maximum Gap   `Hard`   Link
165   Compare Version Numbers   `Medium`   Link
166   Fraction To Recurring Decimal   `Medium`   Link
167   Two Sum II - Input Array Is Sorted   `Easy`   Link
168   Excel Sheet Column Title   `Easy`   Link
169   Majority Element   `Easy`   Link
171   Excel Sheet Column Number   `Easy`   Link
172   Factorial Trailing Zeroes   `Medium`   Link
173   Binary Search Tree Iterator   `Medium`   Link
174   Dungeon Game   `Hard`   Link
179   Largest Number   `Medium`   Link
187   Repeated DNA Sequences   `Medium`   Link
188   Best Time To Buy And Sell Stock IV   `Hard`   Link
189   Rotate Array   `Medium`   Link
190   Reverse Bits   `Easy`   Link
191   Number Of 1 Bits   `Easy`   Link
198   House Robber   `Medium`   Link
199   Binary Tree Right Side View   `Medium`   Link
200   Number of Islands   `Medium`   Link
201   Bitwise And Of Numbers Range   `Medium`   Link
202   Happy Number   `Easy`   Link
203   Remove Linked List Elements   `Easy`   Link
204   Count Primes   `Medium`   Link
205   Isomorphic Strings   `Easy`   Link
206   Reverse Linked List   `Easy`   Link
207   Course Schedule   `Medium`   Link
208   Implement Trie (Prefix Tree)   `Medium`   Link
209   Minimum Size Subarray Sum   `Medium`   Link
210   Course Schedule II   `Medium`   Link
211   Design Add And Search Words Data Structure   `Medium`   Link
212   Word Search II   `Hard`   Link
213   House Robber II   `Medium`   Link
214   Shortest Palindrome   `Hard`   Link
215   Kth Largest Element In An Array   `Medium`   Link
216   Combination Sum III   `Medium`   Link
217   Contains Duplicate   `Easy`   Link
219   Contains Duplicate II   `Easy`   Link
220   Contains Duplicate III   `Medium`   Link
221   Maximal Square   `Medium`   Link
222   Count Complete Tree Nodes   `Medium`   Link
223   Rectangle Area   `Medium`   Link
224   Basic Calculator   `Hard`   Link
225   Implement Stack Using Queues   `Easy`   Link
226   Invert Binary Tree   `Easy`   Link
227   Basic Calculator II   `Medium`   Link
228   Summary Ranges   `Easy`   Link
229   Majority Element II   `Medium`   Link
230   Kth Smallest Element In A BST   `Medium`   Link
231   Power Of Two   `Easy`   Link
232   Implement Queue Using Stacks   `Easy`   Link
233   Number Of Digit One   `Hard`   Link
234   Palindrome Linked List   `Easy`   Link
235   Lowest Common Ancestor Of A Binary Search Tree   `Easy`   Link
236   Lowest Common Ancestor Of A Binary Tree   `Medium`   Link
237   Delete Node In A Linked List   `Medium`   Link
238   Product Of Array Except Self   `Medium`   Link
239   Sliding Window Maximum   `Hard`   Link
240   Search A 2D Matrix II   `Medium`   Link
241   Different Ways To Add Parentheses   `Medium`   Link
242   Valid Anagram   `Easy`   Link
257   Binary Tree Paths   `Easy`   Link
258   Add Digits   `Easy`   Link
260   Single Number Iii   `Medium`   Link
263   Ugly Number   `Easy`   Link
264   Ugly Number II   `Medium`   Link
268   Missing Number   `Easy`   Link
273   Integer To English Words   `Hard`   Link
274   H-Index   `Medium`   Link
275   H-Index II   `Medium`   Link
278   First Bad Version   `Easy`   Link
279   Perfect Squares   `Medium`   Link
282   Expression Add Operators   `Hard`   Link
283   Move Zeroes   `Easy`   Link
284   Peeking Iterator   `Medium`   Link
287   Find The Duplicate Number   `Medium`   Link
289   Game Of Life   `Medium`   Link
290   Word Pattern   `Easy`   Link
292   Nim Game   `Easy`   Link
295   Find Median From Data Stream   `Hard`   Link
297   Serialize And Deserialize Binary Tree   `Hard`   Link
299   Bulls And Cows   `Medium`   Link
300   Longest Increasing Subsequence   `Medium`   Link
301   Remove Invalid Parentheses   `Hard`   Link
303   Range Sum Query - Immutable   `Easy`   Link
304   Range Sum Query 2D - Immutable   `Medium`   Link
306   Additive Number   `Medium`   Link
309   Best Time To Buy And Sell Stock With Cooldown   `Medium`   Link
310   Minimum Height Trees   `Medium`   Link
312   Burst Balloons   `Hard`   Link
313   Super Ugly Number   `Medium`   Link
315   Count Of Smaller Numbers After Self   `Hard`   Link
316   Remove Duplicate Letters   `Medium`   Link
318   Maximum Product Of Word Lengths   `Medium`   Link
319   Bulb Switcher   `Medium`   Link
321   Create Maximum Number   `Hard`   Link
322   Coin Change   `Medium`   Link
326   Power Of Three   `Easy`   Link
327   Count Of Range Sum   `Hard`   Link
328   Odd Even Linked List   `Medium`   Link
329   Longest Increasing Path In A Matrix   `Hard`   Link
330   Patching Array   `Hard`   Link
331   Verify Preorder Serialization Of A Binary Tree   `Medium`   Link
334   Increasing Triplet Subsequence   `Medium`   Link
335   Self Crossing   `Hard`   Link
336   Palindrome Pairs   `Hard`   Link
337   House Robber III   `Medium`   Link
338   Counting Bits   `Easy`   Link
341   Flatten Nested List Iterator   `Medium`   Link
342   Power Of Four   `Easy`   Link
343   Integer Break   `Medium`   Link
344   Reverse String   `Easy`   Link
345   Reverse Vowels Of A String   `Easy`   Link
347   Top K Frequent Elements   `Medium`   Link
349   Intersection Of Two Arrays   `Easy`   Link
350   Intersection Of Two Arrays II   `Easy`   Link
352   Data Stream As Disjoint Intervals   `Hard`   Link
355   Design Twitter   `Medium`   Link
357   Count Numbers With Unique Digits   `Medium`   Link
365   Water And Jug Problem   `Medium`   Link
367   Valid Perfect Square   `Easy`   Link
368   Largest Divisible Subset   `Medium`   Link
371   Sum Of Two Integers   `Medium`   Link
372   Super Pow   `Medium`   Link
373   Find K Pairs With Smallest Sums   `Medium`   Link
374   Guess Number Higher Or Lower   `Easy`   Link
375   Guess Number Higher Or Lower II   `Medium`   Link
376   Wiggle Subsequence   `Medium`   Link
377   Combination Sum IV   `Medium`   Link
378   Kth Smallest Element In A Sorted Matrix   `Medium`   Link
380   Insert Delete GetRandom O(1)   `Easy`   Link
381   Insert Delete Getrandom O(1) - Duplicates Allowed   `Hard`   Link
382   Linked List Random Node   `Medium`   Link
383   Ransom Note   `Easy`   Link
384   Shuffle An Array   `Medium`   Link
385   Mini Parser   `Medium`   Link
386   Lexicographical Numbers   `Medium`   Link
387   First Unique Character In A String   `Easy`   Link
388   Longest Absolute File Path   `Medium`   Link
389   Find The Difference   `Easy`   Link
390   Elimination Game   `Medium`   Link
391   Perfect Rectangle   `Hard`   Link
392   Is Subsequence   `Easy`   Link
393   UTF-8 Validation   `Medium`   Link
394   Decode String   `Medium`   Link
395   Longest Substring With At Least K Repeating Characters   `Medium`   Link
396   Rotate Function   `Medium`   Link
397   Integer Replacement   `Medium`   Link
398   Random Pick Index   `Medium`   Link
399   Evaluate Division   `Medium`   Link
400   Nth Digit   `Medium`   Link
401   Binary Watch   `Easy`   Link
402   Remove K Digits   `Medium`   Link
403   Frog Jump   `Hard`   Link
404   Sum Of Left Leaves   `Easy`   Link
405   Convert A Number To Hexadecimal   `Easy`   Link
406   Queue Reconstruction By Height   `Medium`   Link
407   Trapping Rain Water II   `Hard`   Link
409   Longest Palindrome   `Easy`   Link
410   Split Array Largest Sum   `Hard`   Link
412   Fizz Buzz   `Easy`   Link
413   Arithmetic Slices   `Medium`   Link
414   Third Maximum Number   `Easy`   Link
415   Add Strings   `Easy`   Link
416   Partition Equal Subset Sum   `Medium`   Link
417   Pacific Atlantic Water Flow   `Medium`   Link
419   Battleships In A Board   `Medium`   Link
420   Strong Password Checker   `Hard`   Link
421   Maximum XOR of Two Numbers In An Array   `Medium`   Link
423   Reconstruct Original Digits From English   `Medium`   Link
424   Longest Repeating Character Replacement   `Medium`   Link
427   Construct Quad Tree   `Medium`   Link
429   N-Ary Tree Level Order Traversal   `Medium`   Link
430   Flatten A Multilevel Doubly Linked List   `Medium`   Link
432   All O’One Data Structure   `Hard`   Link
433   Minimum Genetic Mutation   `Medium`   Link
434   Number Of Segments In A String   `Easy`   Link
435   Non-Overlapping Intervals   `Medium`   Link
436   Find Right Interval   `Medium`   Link
437   Path Sum III   `Medium`   Link
438   Find All Anagrams In A String   `Medium`   Link
440   K-Th Smallest In Lexicographical Order   `Hard`   Link
441   Arranging Coins   `Easy`   Link
442   Find All Duplicates In An Array   `Medium`   Link
443   String Compression   `Medium`   Link
445   Add Two Numbers II   `Medium`   Link
446   Arithmetic Slices II - Subsequence   `Hard`   Link
447   Number Of Boomerangs   `Medium`   Link
448   Find All Numbers Disappeared In An Array   `Easy`   Link
449   Serialize And Deserialize BST   `Medium`   Link
450   Delete Node In A BST   `Medium`   Link
451   Sort Characters By Frequency   `Medium`   Link
452   Minimum Number Of Arrows To Burst Balloons   `Medium`   Link
453   Minimum Moves To Equal Array Elements   `Medium`   Link
454   Four Sum II   `Medium`   Link
455   Assign Cookies   `Easy`   Link
456   132 Pattern   `Medium`   Link
457   Circular Array Loop   `Medium`   Link
458   Poor Pigs   `Hard`   Link
459   Repeated Substring Pattern   `Easy`   Link
460   LFU Cache   `Hard`   Link
461   Hamming Distance   `Easy`   Link
462   Minimum Moves To Equal Array Elements II   `Medium`   Link
463   Island Perimeter   `Easy`   Link
464   Can I Win   `Medium`   Link
467   Unique Substrings In Wraparound String   `Medium`   Link
468   Validate IP Address   `Medium`   Link
470   Implement Rand10() Using Rand7()   `Medium`   Link
472   Concatenate Words   `Hard`   Link
473   Matchsticks To Square   `Medium`   Link
474   Ones And Zeroes   `Medium`   Link
475   Heaters   `Medium`   Link
476   Number Complement   `Easy`   Link
477   Total Hamming Distance   `Medium`   Link
478   Generate Random Point In A Circle   `Medium`   Link
479   Largest Palindrome Product   `Hard`   Link
480   Sliding Window Median   `Hard`   Link
481   Magical String   `Medium`   Link
482   License Key Formatting   `Easy`   Link
483   Smallest Good Base   `Hard`   Link
485   Max Consecutive Ones   `Easy`   Link
486   Predict The Winner   `Medium`   Link
488   Zuma Game   `Hard`   Link
491   Increasing Subsequences   `Medium`   Link
492   Construct The Rectangle   `Easy`   Link
493   Reverse Pairs   `Hard`   Link
494   Target Sum   `Medium`   Link
495   Teemo Attacking   `Easy`   Link
496   Next Greater Element I   `Easy`   Link
497   Random Point In Non-Overlapping Rectangles   `Medium`   Link
498   Diagonal Traverse   `Medium`   Link
500   Keyboard Row   `Easy`   Link
501   Find Mode In Binary Search Tree   `Easy`   Link
502   IPO   `Hard`   Link
503   Next Greater Element II   `Medium`   Link
504   Base 7   `Easy`   Link
506   Relative Ranks   `Easy`   Link
507   Perfect Number   `Easy`   Link
508   Most Frequent Subtree Sum   `Medium`   Link
509   Fibonacci Number   `Easy`   Link
513   Find Bottom Left Tree Value   `Medium`   Link
514   Freedom Trail   `Hard`   Link
515   Find Largest Value In Each Tree Row   `Medium`   Link
516   Longest Palindromic Subsequence   `Medium`   Link
517   Super Washing Machines   `Hard`   Link
518   Coin Change II   `Medium`   Link
519   Random Flip Matrix   `Medium`   Link
520   Detect Capital   `Easy`   Link
521   Longest Uncommon Subsequence I   `Easy`   Link
522   Longest Uncommon Subsequence II   `Medium`   Link
523   Continuous Subarray Sum   `Medium`   Link
524   Longest Word In Dictionary Through Deleting   `Medium`   Link
525   Contiguous Array   `Medium`   Link
526   Beautiful Arrangement   `Medium`   Link
528   Random Pick With Weight   `Medium`   Link
529   Minesweeper   `Medium`   Link
530   Minimum Absolute Difference In BST   `Easy`   Link
532   K-Diff Pairs In An Array   `Medium`   Link
535   Encode And Decode TinyURL   `Medium`   Link
537   Complex Number Multiplication   `Medium`   Link
538   Convert BST To Greater Tree   `Medium`   Link
539   Minimum Time Difference   `Medium`   Link
540   Single Element In A Sorted Array   `Medium`   Link
541   Reverse String II   `Easy`   Link
542   01 Matrix   `Medium`   Link
543   Diameter Of Binary Tree   `Easy`   Link
546   Remove Boxes   `Hard`   Link
547   Number Of Provinces   `Medium`   Link
551   Student Attendance Record I   `Easy`   Link
552   Student Attendance Record II   `Hard`   Link
553   Optimal Division   `Medium`   Link
554   Brick Wall   `Medium`   Link
556   Next Greater Element III   `Medium`   Link
557   Reverse Words In A String III   `Easy`   Link
558   Logical Or Of Two Binary Grids Represented As Quad-Trees   `Medium`   Link
559   Maximum Depth Of N-Ary Tree   `Easy`   Link
560   Subarray Sum Equals K   `Medium`   Link
561   Array Partition I   `Easy`   Link
563   Binary Tree Tilt   `Easy`   Link
564   Find The Closest Palindrome   `Hard`   Link
565   Array Nesting   `Medium`   Link
566   Reshape The Matrix   `Easy`   Link
567   Permutation In String   `Medium`   Link
572   Subtree Of Another Tree   `Easy`   Link
575   Distribute Candies   `Easy`   Link
576   Out Of Boundary Paths   `Medium`   Link
581   Shortest Unsorted Continuous Subarray   `Medium`   Link
583   Delete Operation For Two Strings   `Medium`   Link
587   Erect The Fence   `Hard`   Link
589   N-Ary Tree Preorder Traversal   `Easy`   Link
590   N-Ary Tree Postorder Traversal   `Easy`   Link
591   Tag Validator   `Hard`   Link
592   Fraction Addition And Subtraction   `Medium`   Link
593   Valid Square   `Medium`   Link
594   Longest Harmonious Subsequence   `Easy`   Link
598   Range Addition II   `Easy`   Link
599   Minimum Index Sum Of Two Lists   `Easy`   Link
600   Non-Negative Integers Without Consecutive Ones   `Hard`   Link
605   Can Place Flowers   `Easy`   Link
606   Construct String From Binary Tree   `Easy`   Link
609   Find Duplicate File In System   `Medium`   Link
611   Valid Triangle Number   `Medium`   Link
617   Merge Two Binary Trees   `Easy`   Link
621   Task Scheduler   `Medium`   Link
622   Design Circular Queue   `Medium`   Link
623   Add One Row To Tree   `Medium`   Link
628   Maximum Product Of Three Numbers   `Easy`   Link
629   K Inverse Pairs Array   `Hard`   Link
630   Course Schedule III   `Hard`   Link
632   Smallest Range Covering Elements From K Lists   `Hard`   Link
633   Sum Of Square Numbers   `Medium`   Link
636   Exclusive Time Of Functions   `Medium`   Link
637   Average Of Levels In Binary Tree   `Easy`   Link
638   Shopping Offers   `Medium`   Link
639   Decode Ways II   `Hard`   Link
640   Solve The Equation   `Medium`   Link
641   Design Circular Deque   `Medium`   Link
643   Maximum Average Subarray I   `Easy`   Link
645   Set Mismatch   `Easy`   Link
646   Maximum Length Of Pair Chain   `Medium`   Link
647   Palindromic Substrings   `Medium`   Link
648   Replace Words   `Medium`   Link
649   Dota2 Senate   `Medium`   Link
650   2 Keys Keyboard   `Medium`   Link
652   Find Duplicate Subtrees   `Medium`   Link
653   Two Sum IV - Input Is A BST   `Easy`   Link
654   Maximum Binary Tree   `Medium`   Link
655   Print Binary Tree   `Medium`   Link
657   Robot Return To Origin   `Easy`   Link
658   Find K Closest Elements   `Medium`   Link
659   Split Array Into Consecutive Subsequences   `Medium`   Link
661   Image Smoother   `Easy`   Link
662   Maximum Width Of Binary Tree   `Medium`   Link
664   Strange Printer   `Hard`   Link
665   Non-Decreasing Array   `Medium`   Link
667   Beautiful Arrangement II   `Medium`   Link
668   Kth Smallest Number In Multiplication Table   `Hard`   Link
669   Trim A Binary Search Tree   `Medium`   Link
670   Maximum Swap   `Medium`   Link
671   Second Minimum Node In A Binary Tree   `Easy`   Link
672   Bulb Switcher II   `Medium`   Link
673   Number Of Longest Increasing Subsequence   `Medium`   Link
674   Longest Continuous Increasing Subsequence   `Easy`   Link
675   Cut Off Trees For Golf Event   `Hard`   Link
676   Implement Magic Dictionary   `Medium`   Link
677   Map Sum Pairs   `Medium`   Link
678   Valid Parenthesis String   `Medium`   Link
679   24 Game   `Hard`   Link
680   Valid Palindrome II   `Easy`   Link
682   Baseball Game   `Easy`   Link
684   Redundant Connection   `Medium`   Link
685   Redundant Connection II   `Hard`   Link
686   Repeated String Match   `Medium`   Link
687   Longest Univalue Path   `Medium`   Link
688   Knight Probability In Chessboard   `Medium`   Link
689   Maximum Sum Of 3 Non-Overlapping Subarrays   `Hard`   Link
690   Employee Importance   `Medium`   Link
691   Stickers To Spell Word   `Hard`   Link
692   Top K Frequent Words   `Medium`   Link
693   Binary Number With Alternating Bits   `Easy`   Link
695   Max Area Of Island   `Medium`   Link
696   Count Binary Substrings   `Easy`   Link
697   Degree Of An Array   `Easy`   Link
698   Partition To K Equal Sum Subsets   `Medium`   Link
699   Falling Squares   `Hard`   Link
700   Search In A Binary Search Tree   `Easy`   Link
701   Insert Into A Binary Search Tree   `Medium`   Link
703   Kth Largest Element In A Stream   `Easy`   Link
704   Binary Search   `Easy`   Link
705   Design Hashset   `Easy`   Link
706   Design Hashmap   `Easy`   Link
707   Design Linked List   `Medium`   Link
709   To Lower Case   `Easy`   Link
710   Random Pick With Blacklist   `Hard`   Link
712   Minimum Ascii Delete Sum For Two Strings   `Medium`   Link
713   Subarray Product Less Than K   `Medium`   Link
714   Best Time To Buy And Sell Stock With Transaction Fee   `Medium`   Link
715   Range Module   `Hard`   Link
717   1-Bit And 2-Bit Characters   `Easy`   Link
718   Maximum Length Of Repeated Subarray   `Medium`   Link
719   Find K-Th Smallest Pair Distance   `Hard`   Link
720   Longest Word In Dictionary   `Easy`   Link
721   Accounts Merge   `Medium`   Link
722   Remove Comments   `Medium`   Link
724   Find Pivot Index   `Easy`   Link
725   Split Linked List In Parts   `Medium`   Link
726   Number Of Atoms   `Hard`   Link
728   Self Dividing Numbers   `Easy`   Link
729   My Calendar I   `Medium`   Link
730   Count Different Palindromic Subsequences   `Hard`   Link
731   My Calendar II   `Medium`   Link
732   My Calendar III   `Hard`   Link
733   Flood Fill   `Easy`   Link
735   Asteroid Collision   `Medium`   Link
736   Parse Lisp Expression   `Hard`   Link
738   Monotone Increasing Digits   `Medium`   Link
739   Daily Temperatures   `Medium`   Link
740   Delete And Earn   `Medium`   Link
741   Cherry Pickup   `Hard`   Link
743   Network Delay Time   `Medium`   Link
744   Find Smallest Letter Greater Than Target   `Easy`   Link
745   Prefix And Suffix Search   `Hard`   Link
746   Min Cost Climbing Stairs   `Easy`   Link
747   Largest Number At Least Twice Of Others   `Easy`   Link
748   Shortest Completing Word   `Easy`   Link
749   Contain Virus   `Hard`   Link
752   Open The Lock   `Medium`   Link
753   Cracking The Safe   `Hard`   Link
754   Reach A Number   `Medium`   Link
756   Pyramid Transition Matrix   `Medium`   Link
757   Set Intersection Size At Least Two   `Hard`   Link
761   Special Binary String   `Hard`   Link
762   Prime Number Of Set Bits In Binary Representation   `Easy`   Link
763   Partition Labels   `Medium`   Link
764   Largest Plus Sign   `Medium`   Link
765   Couples Holding Hands   `Hard`   Link
766   Toeplitz Matrix   `Easy`   Link
767   Reorganize String   `Medium`   Link
768   Max Chunks To Make Sorted II   `Hard`   Link
769   Max Chunks To Make Sorted   `Medium`   Link
770   Basic Calculator IV   `Hard`   Link
771   Jewels And Stones   `Easy`   Link
773   Sliding Puzzle   `Hard`   Link
775   Global And Local Inversions   `Medium`   Link
777   Swap Adjacent In LR String   `Medium`   Link
778   Swim In Rising Water   `Hard`   Link
779   K-Th Symbol In Grammar   `Medium`   Link
780   Reaching Points   `Hard`   Link
781   Rabbits In Forest   `Medium`   Link
782   Transform To Chessboard   `Hard`   Link
783   Minimum Distance Between Bst Nodes   `Easy`   Link
784   Letter Case Permutation   `Medium`   Link
785   Is Graph Bipartite?   `Medium`   Link
786   K-Th Smallest Prime Fraction   `Hard`   Link
787   Cheapest Flights Within K Stops   `Medium`   Link
788   Rotated Digits   `Medium`   Link
789   Escape The Ghosts   `Medium`   Link
790   Domino And Tromino Tiling   `Medium`   Link
791   Custom Sort String   `Medium`   Link
792   Number Of Matching Subsequences   `Medium`   Link
793   Preimage Size Of Factorial Zeroes Function   `Hard`   Link
794   Valid Tic-Tac-Toe State   `Medium`   Link
795   Number Of Subarrays With Bounded Maximum   `Medium`   Link
796   Rotate String   `Easy`   Link
797   All Paths From Source To Target   `Medium`   Link
798   Smallest Rotation With Highest Score   `Hard`   Link
799   Champagne Tower   `Medium`   Link
801   Minimum Swaps To Make Sequences Increasing   `Hard`   Link
802   Find Eventual Safe States   `Medium`   Link
803   Bricks Falling When Hit   `Hard`   Link
804   Unique Morse Code Words   `Easy`   Link
805   Split Array With Same Average   `Hard`   Link
806   Number Of Lines To Write String   `Easy`   Link
807   Max Increase To Keep City Skyline   `Medium`   Link
808   Soup Servings   `Medium`   Link
809   Expressive Words   `Medium`   Link
810   Chalkboard Xor Game   `Hard`   Link
811   Subdomain Visit Count   `Medium`   Link
812   Largest Triangle Area   `Easy`   Link
813   Largest Sum Of Averages   `Medium`   Link
814   Binary Tree Pruning   `Medium`   Link
815   Bus Routes   `Hard`   Link
816   Ambiguous Coordinates   `Medium`   Link
817   Linked List Components   `Medium`   Link
818   Race Car   `Hard`   Link
819   Most Common Word   `Easy`   Link
820   Short Encoding Of Words   `Medium`   Link
821   Shortest Distance To A Character   `Easy`   Link
822   Card Flipping Game   `Medium`   Link
823   Binary Trees With Factors   `Medium`   Link
824   Goat Latin   `Easy`   Link
825   Friends Of Appropriate Ages   `Medium`   Link
826   Most Profit Assigning Work   `Medium`   Link
827   Making A Large Island   `Hard`   Link
828   Count Unique Characters Of All Substrings Of A Given String   `Hard`   Link
829   Consecutive Numbers Sum   `Hard`   Link
830   Positions Of Large Groups   `Easy`   Link
831   Masking Personal Information   `Medium`   Link
832   Flipping An Image   `Easy`   Link
833   Find And Replace In String   `Medium`   Link
834   Sum Of Distances In Tree   `Hard`   Link
835   Image Overlap   `Medium`   Link
836   Rectangle Overlap   `Easy`   Link
837   New 21 Game   `Medium`   Link
838   Push Dominoes   `Medium`   Link
839   Similar String Groups   `Hard`   Link
840   Magic Squares In Grid   `Medium`   Link
841   Keys And Rooms   `Medium`   Link
842   Split Array Into Fibonacci Sequence   `Medium`   Link
843   Guess The Word   `Hard`   Link
844   Backspace String Compare   `Easy`   Link
845   Longest Mountain In Array   `Medium`   Link
846   Hand Of Straights   `Medium`   Link
847   Shortest Path Visiting All Nodes   `Hard`   Link
848   Shifting Letters   `Medium`   Link
849   Maximize Distance To Closest Person   `Medium`   Link
850   Rectangle Area II   `Hard`   Link
851   Loud And Rich   `Medium`   Link
852   Peak Index In A Mountain Array   `Easy`   Link
853   Car Fleet   `Medium`   Link
854   K-Similar Strings   `Hard`   Link
855   Exam Room   `Medium`   Link
856   Score Of Parentheses   `Medium`   Link
857   Minimum Cost To Hire K Workers   `Hard`   Link
858   Mirror Reflection   `Medium`   Link
859   Buddy Strings   `Easy`   Link
860   Lemonade Change   `Easy`   Link
861   Score After Flipping Matrix   `Medium`   Link
862   Shortest Subarray With Sum At Least K   `Hard`   Link
863   All Nodes Distance K In Binary Tree   `Medium`   Link
864   Shortest Path To Get All Keys   `Hard`   Link
865   Smallest Subtree With All The Deepest Nodes   `Medium`   Link
866   Prime Palindrome   `Medium`   Link
867   Transpose Matrix   `Easy`   Link
868   Binary Gap   `Easy`   Link
869   Reordered Power Of 2   `Medium`   Link
870   Advantage Shuffle   `Medium`   Link
871   Minimum Number Of Refueling Stops   `Hard`   Link
872   Leaf-Similar Trees   `Easy`   Link
873   Length Of Longest Fibonacci Subsequence   `Medium`   Link
874   Walking Robot Simulation   `Medium`   Link
875   Koko Eating Bananas   `Medium`   Link
876   Middle Of The Linked List   `Easy`   Link
877   Stone Game   `Medium`   Link
878   Nth Magical Number   `Hard`   Link
879   Profitable Schemes   `Hard`   Link
880   Decoded String At Index   `Medium`   Link
881   Boats To Save People   `Medium`   Link
882   Reachable Nodes In Subdivided Graph   `Hard`   Link
883   Projection Area Of 3D Shapes   `Easy`   Link
884   Uncommon Words From Two Sentences   `Easy`   Link
885   Spiral Matrix III   `Medium`   Link
886   Possible Bipartition   `Medium`   Link
887   Super Egg Drop   `Hard`   Link
888   Fair Candy Swap   `Easy`   Link
889   Construct Binary Tree From Preorder And Postorder Traversal   `Medium`   Link
890   Find And Replace Pattern   `Medium`   Link
891   Sum Of Subsequence Widths   `Hard`   Link
892   Surface Area Of 3D Shapes   `Easy`   Link
893   Groups Of Special-Equivalent Strings   `Medium`   Link
894   All Possible Full Binary Trees   `Medium`   Link
895   Maximum Frequency Stack   `Hard`   Link
896   Monotonic Array   `Easy`   Link
897   Increasing Order Search Tree   `Easy`   Link
898   Bitwise Ors Of Subarrays   `Medium`   Link
899   Orderly Queue   `Hard`   Link
900   Rle Iterator   `Medium`   Link
901   Online Stock Span   `Medium`   Link
902   Numbers At Most N Given Digit Set   `Hard`   Link
903   Valid Permutations For DI Sequence   `Hard`   Link
904   Fruit Into Baskets   `Medium`   Link
905   Sort Array By Parity   `Easy`   Link
906   Super Palindromes   `Hard`   Link
907   Sum Of Subarray Minimums   `Medium`   Link
908   Smallest Range I   `Easy`   Link
909   Snakes And Ladders   `Medium`   Link
910   Smallest Range II   `Medium`   Link
911   Online Election   `Medium`   Link
912   Sort An Array   `Medium`   Link
913   Cat And Mouse   `Hard`   Link
914   X Of A Kind In A Deck Of Cards   `Easy`   Link
915   Partition Array Into Disjoint Intervals   `Medium`   Link
916   Word Subsets   `Medium`   Link
917   Reverse Only Letters   `Easy`   Link
918   Maximum Sum Circular Subarray   `Medium`   Link
919   Complete Binary Tree Inserter   `Medium`   Link
920   Number Of Music Playlists   `Hard`   Link
921   Minimum Add To Make Parentheses Valid   `Medium`   Link
922   Sort Array By Parity II   `Easy`   Link
923   3Sum With Multiplicity   `Medium`   Link
924   Minimize Malware Spread   `Hard`   Link
925   Long Pressed Name   `Easy`   Link
926   Flip String To Monotone Increasing   `Medium`   Link
927   Three Equal Parts   `Hard`   Link
928   Minimize Malware Spread II   `Hard`   Link
929   Unique Email Addresses   `Easy`   Link
930   Binary Subarrays With Sum   `Medium`   Link
931   Minimum Falling Path Sum   `Medium`   Link
932   Beautiful Array   `Medium`   Link
933   Number Of Recent Calls   `Easy`   Link
934   Shortest Bridge   `Medium`   Link
935   Knight Dialer   `Medium`   Link
936   Stamping The Sequence   `Hard`   Link
937   Reorder Data In Log Files   `Easy`   Link
938   Range Sum Of BST   `Easy`   Link
939   Minimum Area Rectangle   `Medium`   Link
940   Distinct Subsequences II   `Hard`   Link
941   Valid Mountain Array   `Easy`   Link
942   DI String Match   `Easy`   Link
943   Find The Shortest Superstring   `Hard`   Link
944   Delete Columns To Make Sorted   `Easy`   Link
945   Minimum Increment To Make Array Unique   `Medium`   Link
946   Validate Stack Sequences   `Medium`   Link
947   Most Stones Removed With Same Row Or Column   `Medium`   Link
948   Bag Of Tokens   `Medium`   Link
949   Largest Time For Given Digits   `Medium`   Link
950   Reveal Cards In Increasing Order   `Medium`   Link
951   Flip Equivalent Binary Trees   `Medium`   Link
952   Largest Component Size By Common Factor   `Hard`   Link
953   Verifying An Alien Dictionary   `Easy`   Link
954   Array Of Doubled Pairs   `Medium`   Link
955   Delete Columns To Make Sorted II   `Medium`   Link
956   Tallest Billboard   `Hard`   Link
957   Prison Cells After N Days   `Medium`   Link
958   Check Completeness Of A Binary Tree   `Medium`   Link
959   Regions Cut By Slashes   `Medium`   Link
960   Delete Columns To Make Sorted III   `Hard`   Link
961   N-Repeated Element In Size 2N Array   `Easy`   Link
962   Maximum Width Ramp   `Medium`   Link
963   Minimum Area Rectangle II   `Medium`   Link
964   Least Operators To Express Number   `Hard`   Link
965   Univalued Binary Tree   `Easy`   Link
966   Vowel Spellchecker   `Medium`   Link
967   Numbers With Same Consecutive Differences   `Medium`   Link
968   Binary Tree Cameras   `Hard`   Link
969   Pancake Sorting   `Medium`   Link
970   Powerful Integers   `Medium`   Link
971   Flip Binary Tree To Match Preorder Traversal   `Medium`   Link
972   Equal Rational Numbers   `Hard`   Link
973   K Closest Points To Origin   `Medium`   Link
974   Subarray Sum Divisible By K   `Medium`   Link
975   Odd Even Jump   `Hard`   Link
976   Largest Perimeter Triangle   `Easy`   Link
977   Squares Of A Sorted Array   `Easy`   Link
978   Longest Turbulent Subarray   `Medium`   Link
979   Distribute Coins In Binary Tree   `Medium`   Link
980   Unique Paths III   `Hard`   Link
981   Time Based Key-Value Store   `Medium`   Link
982   Triples With Bitwise And Equal To Zero   `Hard`   Link
983   Minimum Cost For Tickets   `Medium`   Link
984   String Without Aaa Or Bbb   `Medium`   Link
985   Sum Of Even Numbers After Queries   `Medium`   Link
986   Interval List Intersections   `Medium`   Link
987   Vertical Order Traversal Of A Binary Tree   `Hard`   Link
988   Smallest String Starting From Leaf   `Medium`   Link
989   Add To Array-Form Of Integer   `Easy`   Link
990   Satisfiability Of Equality Equations   `Medium`   Link
991   Broken Calculator   `Medium`   Link
992   Subarrays With K Different Integers   `Hard`   Link
993   Cousins In Binary Tree   `Easy`   Link
994   Rotting Oranges   `Medium`   Link
995   Minimum Number Of K Consecutive Bit Flips   `Hard`   Link
996   Number Of Squareful Arrays   `Hard`   Link
997   Find The Town Judge   `Easy`   Link
998   Maximum Binary Tree II   `Medium`   Link
999   Available Captures For Rook   `Easy`   Link
1000   Minimum Cost To Merge Stones   `Hard`   Link
1023   Camelcase Matching   `Medium`   Link
1032   Stream Of Characters   `Hard`   Link
1099   Two Sum Less Than K   `Easy`   Link
1213   Intersection Of Three Sorted Arrays   `Easy`   Link
1224   Maximum Equal Frequency   `Hard`   Link
1438   Longest Continuous Subarray With Absolute Diff Less Than Or Equal To Limit   `Medium`   Link
1521   Number Of Good Pairs   `Easy`   Link
1539   Kth Missing Positive Number   `Easy`   Link
1539   Kth Missing Positive Number   `Easy`   Link
1748   Sum Of Unique Elements   `Easy`   Link
1812   Determine Color Of A Chessboard Square   `Easy`   Link
1902   Depth of BST Given Insertion Order   `Medium`   Link
1999   Smallest Greater Multiple Made of Two Digits   `Medium`   Link
2000   Reverse Prefix of Word   `Easy`   Link

Database

No.   Problem   Difficulty   Solution
175   Combine Two Tables   `Easy`   Link
176   Second Highest Salary   `Easy`   Link
177   Nth Highest Salary   `Medium`   Link
178   Rank Scores   `Medium`   Link
180   Consecutive Numbers   `Medium`   Link
181   Employees Earning More Than Their Managers   `Easy`   Link
182   Duplicate Emails   `Easy`   Link
183   Customers Who Never Order   `Easy`   Link
184   Department Highest Salary   `Medium`   Link
185   Department Top Three Salaries   `Hard`   Link
196   Delete Duplicate Emails   `Easy`   Link
197   Rising Temperature   `Easy`   Link
262   Trips And Users   `Hard`   Link
511   Game Play Analysis I   `Easy`   Link
512   Game Play Analysis II   `Easy`   Link
534   Game Play Analysis III   `Medium`   Link
550   Game Play Analysis IV   `Medium`   Link
569   Median Employee Salary   `Hard`   Link
570   Managers With At Least 5 Direct Reports   `Medium`   Link
571   Find Median Given Frequency Of Numbers   `Hard`   Link
574   Winning Candidate   `Medium`   Link
577   Employee Bonus   `Easy`   Link
578   Get Highest Answer Rate Question   `Medium`   Link
579   Find Cumulative Salary Of An Employee   `Hard`   Link
580   Count Student Number In Departments   `Medium`   Link
584   Find Customer Referee   `Easy`   Link
585   Investments In 2016   `Medium`   Link
586   Customer Placing The Largest Number Of Orders   `Easy`   Link
595   Big Countries   `Easy`   Link
596   Classes More Than 5 Students   `Easy`   Link
597   Friend Requests I: Overall Acceptance Rate   `Easy`   Link
601   Human Traffic Of Stadium   `Hard`   Link
602   Friend Requests II: Who Has The Most Friends   `Medium`   Link
603   Consecutive Available Seats   `Easy`   Link
607   Sales Person   `Easy`   Link
608   Tree Node   `Medium`   Link
610   Triangle Judgement   `Easy`   Link
612   Shortest Distance In A Plane   `Medium`   Link
613   Shortest Distance In A Line   `Easy`   Link
614   Second Degree Follower   `Medium`   Link
615   Average Salary: Departments VS Company   `Hard`   Link
618   Students Report By Geography   `Hard`   Link
619   Biggest Single Number   `Easy`   Link
620   Not Boring Movies   `Easy`   Link
626   Exchange Seats   `Medium`   Link
627   Swap Salary   `Easy`   Link
1045   Customers Who Bought All Products   `Medium`   Link
1050   Actors And Directors Who Cooperated At Least Three Times   `Easy`   Link
1068   Product Sales Analysis I   `Easy`   Link
1069   Product Sales Analysis II   `Easy`   Link
1070   Product Sales Analysis III   `Medium`   Link
1075   Project Employees I   `Easy`   Link
1076   Project Employees II   `Easy`   Link
1077   Project Employees III   `Medium`   Link
1082   Sales Analysis I   `Easy`   Link
1083   Sales Analysis II   `Easy`   Link
1084   Sales Analysis III   `Easy`   Link
1097   Game Play Analysis V   `Hard`   Link
1098   Unpopular Books   `Medium`   Link
1107   New Users Daily Count   `Medium`   Link
1112   Highest Grade For Each Student   `Medium`   Link
1113   Reported Posts   `Easy`   Link
1126   Active Business   `Medium`   Link
1127   User Purchase Platform   `Hard`   Link
1132   Reported Posts II   `Medium`   Link
1141   User Activity For The Past 30 Days I   `Easy`   Link
1142   User Activity For The Past 30 Days II   `Easy`   Link
1148   Article Views I   `Easy`   Link
1149   Article Views II   `Medium`   Link
1158   Market Analysis I   `Medium`   Link
1159   Market Analysis II   `Hard`   Link
1164   Product Price At A Given Date   `Medium`   Link
1173   Immediate Food Delivery I   `Easy`   Link
1174   Immediate Food Delivery II   `Medium`   Link
1179   Reformat Department Table   `Easy`   Link
1193   Monthly Transactions I   `Medium`   Link
1194   Tournament Winners   `Hard`   Link
1204   Last Person To Fit In The Elevator   `Medium`   Link
1205   Monthly Transactions II   `Medium`   Link
1211   Queries Quality And Percentage   `Easy`   Link
1212   Team Scores In Football Tournament   `Medium`   Link
1225   Report Contiguous Dates   `Hard`   Link
1241   Number Of Comments Per Post   `Easy`   Link
1251   Average Selling Price   `Easy`   Link
1264   Page Recommendations   `Medium`   Link
1270   All People Report To The Given Manager   `Medium`   Link
1280   Students And Examinations   `Easy`   Link
1285   Find The Start And End Number Of Continuous Ranges   `Medium`   Link
1294   Weather Type In Each Country   `Easy`   Link
1303   Find The Team Size   `Easy`   Link
1308   Running Total For Different Genders   `Medium`   Link
1321   Restaurant Growth   `Medium`   Link
1322   Ads Performance   `Easy`   Link
1327   List The Products Ordered In A Period   `Easy`   Link
1336   Number Of Transactions Per Visit   `Hard`   Link
1341   Movie Rating   `Medium`   Link
1350   Students With Invalid Departments   `Easy`   Link
1355   Activity Participants   `Medium`   Link
1364   Number Of Trusted Contacts Of A Customer   `Medium`   Link
1369   Get The Second Most Recent Activity   `Hard`   Link
1378   Replace Employee ID With The Unique Identifier   `Easy`   Link
1384   Total Sales Amount By Year   `Hard`   Link
1393   Capital Gain/Loss   `Medium`   Link
1398   Customers Who Bought Products A And B But Not C   `Medium`   Link
1407   Top Travellers   `Easy`   Link
1412   Find The Quiet Students In All Exams   `Hard`   Link
1421   NPV Queries   `Medium`   Link
1435   Create A Session Bar Chart   `Easy`   Link
1440   Evaluate Boolean Expression   `Medium`   Link
1445   Apples & Oranges   `Medium`   Link
1454   Active Users   `Medium`   Link
1459   Rectangles Area   `Medium`   Link
1468   Calculate Salaries   `Medium`   Link
1479   Sales By Day Of The Week   `Hard`   Link
1484   Group Sold Products By The Date   `Easy`   Link
1495   Friendly Movies Streamed Last Month   `Easy`   Link
1501   Countries You Can Safely Invest In   `Medium`   Link
1511   Customer Order Frequency   `Easy`   Link
1517   Find Users With Valid Emails   `Easy`   Link
1527   Patients With A Condition   `Easy`   Link
1532   The Most Recent Three Orders   `Medium`   Link
1543   Fix Product Name Format   `Easy`   Link
1549   The Most Recent Orders For Each Product   `Medium`   Link
1555   Bank Account Summary   `Medium`   Link
1565   Unique Orders And Customers Per Month   `Easy`   Link
1571   Warehouse Manager   `Easy`   Link
1581   Customer Who Visited But Did Not Make Any Transactions   `Easy`   Link
1587   Bank Account Summary II   `Easy`   Link
1596   The Most Frequently Ordered Products For Each Customer   `Medium`   Link
1607   Sellers With No Sales   `Easy`   Link
1613   Find The Missing IDs   `Medium`   Link
1623   All Valid Triplets That Can Represent A Country   `Easy`   Link
1633   Percentage Of Users Attended A Contest   `Easy`   Link
1635   Hopper Company Queries I   `Hard`   Link
1645   Hopper Company Queries II   `Hard`   Link
1651   Hopper Company Queries III   `Hard`   Link
1661   Average Time Of Process Per Machine   `Easy`   Link
1667   Fix Names In A Table   `Easy`   Link
1677   Product’s Worth Over Invoices   `Easy`   Link
1683   Invalid Tweets   `Easy`   Link
1693   Daily Leads And Partners   `Easy`   Link
1699   Number Of Calls Between Two Persons   `Medium`   Link
1709   Biggest Window Between Visits   `Medium`   Link
1715   Count Apples And Oranges   `Medium`   Link
1729   Find Followers Count   `Easy`   Link
1731   The Number Of Employees Which Report To Each Employee   `Easy`   Link
1741   Find Total Time Spent By Each Employee   `Easy`   Link
1747   Leetflex Banned Accounts   `Medium`   Link
1757   Recyclable And Low Fat Products   `Easy`   Link
1767   Find The Subtasks That Did Not Execute   `Hard`   Link
1777   Product’s Price For Each Store   `Easy`   Link
1783   Grand Slam Titles   `Medium`   Link
1789   Primary Department For Each Employee   `Easy`   Link
1795   Rearrange Products Table   `Easy`   Link
1809   Ad-Free Sessions Table   `Easy`   Link
1811   Find Interview Candidates   `Medium`   Link
1821   Find Customers With Positive Revenue this Year   `Easy`   Link
1831   Maximum Transaction Each Day   `Medium`   Link
1841   League Statistics   `Medium`   Link
1843   Suspicious Bank Accounts   `Medium`   Link
1853   Convert Date Format   `Easy`   Link
1867   Orders With Maximum Quantity Above Average   `Medium`   Link
1873   Calculate Special Bonus   `Easy`   Link
1875   Group Employees of the Same Salary   `Medium`   Link
1890   The Latest Login in 2020   `Easy`   Link
1892   Page Recommendations II   `Hard`   Link
1907   Count Salary Categories   `Medium`   Link
1917   Leetcodify Friends Recommendations   `Hard`   Link
1919   Leetcodify Similar Friends   `Hard`   Link
1934   Confirmation Rate   `Medium`   Link
1939   Users That Actively Request Confirmation Messages   `Easy`   Link
1949   Strong Friendship   `Medium`   Link
1951   All the Pairs With the Maximum Number of Common Followers   `Medium`   Link
1965   Employees With Missing Information   `Easy`   Link
1972   First and Last Call On the Same Day   `Hard`   Link
1978   Employees Whose Manager Left the Company   `Easy`   Link
1988   Find Cutoff Score for Each School   `Medium`   Link
1990   Count the Number of Experiments   `Medium`   Link