| 4. Median of Two Sorted Arrays | | | Solve | Hard | | |
| 15. 3Sum | | | Solve | Medium | | |
| 22. Generate Parentheses | | | Solve | Medium | | |
| 23. Merge k Sorted Lists | | | Solve | Hard | | |
| 25. Reverse Nodes in k-Group | | | Solve | Hard | | |
| 31. Next Permutation | | | Solve | Medium | | |
| 32. Longest Valid Parentheses | | | Solve | Hard | | |
| 33. Search in Rotated Sorted Array | | | Solve | Medium | | |
| 34. Find First and Last Position of Element in Sorted Array | | | Solve | Medium | | |
| 39. Combination Sum | | | Solve | Medium | | |
| 46. Permutations | | | Solve | Medium | | |
| 51. N-Queens | | | Solve | Hard | | |
| 52. N-Queens II | | | Solve | Hard | | |
| 53. Maximum Subarray | | | Solve | Medium | | |
| 56. Merge Intervals | | | Solve | Medium | | |
| 62. Unique Paths | | | Solve | Medium | | |
| 66. Plus One | | | Solve | Easy | | |
| 84. Largest Rectangle in Histogram | | | Solve | Hard | | |
| 93. Restore IP Addresses | | | Solve | Medium | | |
| 105. Construct Binary Tree from Preorder and Inorder Traversal | | | Solve | Medium | | |
| 121. Best Time to Buy and Sell Stock | | | Solve | Easy | | |
| 122. Best Time to Buy and Sell Stock II | | | Solve | Medium | | |
| 124. Binary Tree Maximum Path Sum | | | Solve | Hard | | |
| 139. Word Break | | | Solve | Medium | | |
| 146. LRU Cache | | | Solve | Medium | | |
| 148. Sort List | | | Solve | Medium | | |
| 200. Number of Islands | | | Solve | Medium | | |
| 208. Implement Trie (Prefix Tree) | | | Solve | Medium | | |
| 210. Course Schedule II | | | Solve | Medium | | |
| 215. Kth Largest Element in an Array | | | Solve | Medium | | |
| 221. Maximal Square | | | Solve | Medium | | |
| 224. Basic Calculator | | | Solve | Hard | | |
| 227. Basic Calculator II | | | Solve | Medium | | |
| 228. Summary Ranges | | | Solve | Easy | | |
| 239. Sliding Window Maximum | | | Solve | Hard | | |
| 295. Find Median from Data Stream | | | Solve | Hard | | |
| 300. Longest Increasing Subsequence | | | Solve | Medium | | |
| 378. Kth Smallest Element in a Sorted Matrix | | | Solve | Medium | | |
| 386. Lexicographical Numbers | | | Solve | Medium | | |
| 394. Decode String | | | Solve | Medium | | |
| 403. Frog Jump | | | Solve | Hard | | |
| 410. Split Array Largest Sum | | | Solve | Hard | | |
| 440. K-th Smallest in Lexicographical Order | | | Solve | Hard | | |
| 445. Add Two Numbers II | | | Solve | Medium | | |
| 490. The Maze | | | Solve | Medium | | |
| 505. The Maze II | | | Solve | Medium | | |
| 518. Coin Change II | | | Solve | Medium | | |
| 523. Continuous Subarray Sum | | | Solve | Medium | | |
| 542. 01 Matrix | | | Solve | Medium | | |
| 567. Permutation in String | | | Solve | Medium | | |
