LeetCode My codes for some problems in Leet Code Solved problems Title Solutions Time Space Difficulty 1. Two sum up Code O(N) O(N) Easy 2. Add two numbers Code O(N+M) O(1) Medium 3. Longest Substring Without Repeating Characters Code O(N) O(1) Medium 4. Median of Two Sorted Arrays Code O(log(n+m)) O(log(n+m)) Hard 5. Longest Palindromic Substring Code O(N^2) O(1) Medium 7. Reverse Integer Code O(1) O(1) Easy 10. Regular Expression Matching Code O(NM) O(NM) Hard 11. Container With Most Water Code O(N) O(1) Medium 15. 3Sum Code O(N^2) O(N^2) Medium 17. Letter Combinations of a Phone Number Code O(N) O(N) Medium 19. Remove Nth Node From End of List Code O(N) O(1) Medium 20. Valid Parantheses Code O(N) O(1) Easy 21. Merge Two Sorted Lists Code O(N+M) O(N+M) Easy 22. Generate Parentheses Code O(2^N?) O(2^N?) Medium 23. Merge k Sorted Lists Code O(NlogK) O(NK) Hard 24. Swap Nodes in Pairs Code O(N) O(N) Medium 25. Reverse Nodes in k-Group Code O(N) O(N) Hard 26. Remove Duplicates from Sorted Array Code O(N) O(1) Easy 29. Divide Two Integers Code O() O() __ 31. Next Permutation Code O(N) O(1) Medium 32. Longest Valid Parantheses Code O() O() __ 33. Search in Rotated Sorted Array Code O() O() __ 34. Search for a Range Code O() O() __ 36. Valid Sudoku Code O() O() __ 37. Sudoku Solver Code O(?) O(?) Hard 41. First Missing Positive Code O() O() __ 42. Trapping Rain Water Code O(N) O(N) Hard 44. Wildcard Matching Code O(NM) O(NM) Hard 45. Jump Game II Code O(N) O(1) Hard 49. Group Anagrams Code O(NMlogM) O(NM) Medium 50. Pow(x,n) Code O() O() __ 51. N-Queens Code O(N!) O(N!) Hard 52. N-Queens II Code O(N^N) O(N) Hard 55. Jump Game Code O(N) O(1) Medium 56. Merge Intervals Code O(Nlog(N)) O(N) Medium 66. Unique Paths Code O(MN) O(MN) Medium 72. Edit Distance Code O(MN) O(MN) Hard 75. Sort Colors Code O(N) O(1) Medium 76. Minimum Window Substring Code O(N) O(1) Hard 79. Word Search Code O(NMK) O(N^2) Medium 84. Largest Rectangle in Histogram Code O(N), O(Nlog(N)) O(N) Hard 88. Merge Sorted Array Code O(N+M) O(1) Easy 91. Decode Ways Code O(N) O(N) Medium 94. Binary Tree Inorder Traversal Code O(N) O(N) Medium 98. Validate Binary Search Tree Code O(N) O(1) Medium 102. Binary Tree Level Order Traversal Code O(N) O(N) Medium 103. Binary Tree Zigzag Level Order Traversal Code O(N) O(N) Medium 116. Populating Next Right Pointers in Each Node Code O(N) O(1) Medium 124. Binary Tree Maximum Path Sum Code O(N) O(N) Hard 127. Word Ladder Code O(M) O(M) Medium 128. Longest Consecutive Sequence Code O(N) O(N) Hard 132. Palindrome Partitioning II Code O(N^2) O(N^2) Hard 139. Word Break Code O(N^2+M) O(N+M) Medium 140. Word Break II Code O(N^2*log(M)) O(N^2+M) Hard 145. Binary Tree Postorder Traversal Code O(N) O(N) Hard 146. LRU Cache Code O(1), O(1) O(1), O(1) Hard 149. Max Points on a Line Code O(N^2log(N)) O(N) Hard 153. Find Minimum in Rotated Sorted Array Code O(log(N)) O(1) Medium 154. Find Minimum in Rotated Sorted Array II Code O(N) O(1) Hard 162. Find Peak Element Code O(log N) O(log N) Medium 174. Dungeon Game Code O(NM) O(M) Hard 179. Largest Number Code O(NlogN) O(1) Medium 200. Number of Islands Code O(NM) O(NM) Medium 207. Course Schedule Code O(N+M) O(N+M) Medium 208. Implement Trie (Prefix Tree) Code O() O() Medium 210. Course Schedule II Code O(N+M) O(N+M) Medium 212. Word Search II Code O(NM+K) O(NM+K) Hard 236. Lowest Common Ancestor of a Binary Tree Code O(N) O(N) Medium 239. Sliding Window Maximum Code O(N) O(K) Hard 295. Find Median from Data Stream Code O(logN), O(1) O(1), O(1) Hard 297. Serialize and Deserialize Binary Tree Code O(N), O(N^2) O(N), O(N) Hard 301. Remove Invalid Parentheses Code O(?) O(?) Hard 310. Minimum Height Trees Code O(N) O(N) Medium 312. Burst Balloons Code O(N^3) O(N^2) Hard 315. Count of Smaller Numbers After Self Code O(Nlog(N)) O(Nlog(N)) Hard 322. Coin Change Code O(NM) O(M) Medium 329. Longest Increasing Path in a Matrix Code O(NM) O(NM) Hard 336. Palindrome Pairs Code O(NK^2) O(NK) Hard 347. Top K Frequent Elements Code O(Nlog(K)) O(N) Medium 352. Data Stream as Disjoint Intervals Code O(log(N)) O(N) Hard 354. Russian Doll Envelopes Code O(Nlog(N)) O(N) Hard 378. Kth Smallest Element in a Sorted Matrix Code O(N*(max-min)) O(1) Medium 395. Longest Substring with At Least K Repeating Characters Code O(N) O(1) Medium 403. Frog Jump Code O(N^2) O(N) Hard 407. Trapping Rain Water II Code O(N^2 M) O(NM) Hard 410. Split Array Largest Sum Code O(N^2M) O(NM) Hard 446. Arithmetic Slices II - Subsequence Code O(N^2) O(N^2) Hard 460. LFU Cache Code O(1), O(1) O(1), O(1) Hard 493. Reverse Pairs Code O(Nlog(N)) O(Nlog(N)) Hard 629. K Inverse Pairs Array Code O(NK) O(NK) Hard 630. Course Schedule III Code O(Nlog(N)) O(N) Hard 632. Smallest Range Code O(K*N) O(K) Hard 668. Kth Smallest Number in Multiplication Table Code O(Nlog(max-min)) O(1) Hard 689. Maximum Sum of 3 Non-Overlapping Subarrays Code O(N) O(N) Hard