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
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
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
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
834   Sum Of Distances In Tree   Hard   Link
836   Rectangle Overlap   Easy   Link
837   New 21 Game   Medium   Link
839   Similar String Groups   Hard   Link
840   Magic Squares In Grid   Medium   Link
842   Split Array Into Fibonacci Sequence   Medium   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
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
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
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
872   Leaf-Similar Trees   Easy   Link
873   Length Of Longest Fibonacci Subsequence   Medium   Link
874   Walking Robot Simulation   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
886   Possible Bipartition   Medium   Link
887   Super Egg Drop   Hard   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
907   Sum Of Subarray Minimums   Medium   Link
908   Smallest Range I   Easy   Link
909   Snakes And Ladders   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
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
941   Valid Mountain Array   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
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
964   Least Operators To Express Number   Hard   Link
965   Univalued Binary Tree   Easy   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
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
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
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





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