| 1. Two Sum | | | Solve | Easy | | |
| 3. Longest Substring Without Repeating Characters | | | Solve | Medium | | |
| 4. Median of Two Sorted Arrays | | | Solve | Hard | | |
| 5. Longest Palindromic Substring | | | Solve | Medium | | |
| 15. 3Sum | | | Solve | Medium | | |
| 17. Letter Combinations of a Phone Number | | | Solve | Medium | | |
| 19. Remove Nth Node From End of List | | | Solve | Medium | | |
| 22. Generate Parentheses | | | Solve | Medium | | |
| 23. Merge k Sorted Lists | | | Solve | Hard | | |
| 31. Next Permutation | | | Solve | Medium | | |
| 33. Search in Rotated Sorted Array | | | Solve | Medium | | |
| 38. Count and Say | | | Solve | Medium | | |
| 41. First Missing Positive | | | Solve | Hard | | |
| 46. Permutations | | | Solve | Medium | | |
| 49. Group Anagrams | | | Solve | Medium | | |
| 50. Pow(x, n) | | | Solve | Medium | | |
| 53. Maximum Subarray | | | Solve | Medium | | |
| 56. Merge Intervals | | | Solve | Medium | | |
| 62. Unique Paths | | | Solve | Medium | | |
| 68. Text Justification | | | Solve | Hard | | |
| 112. Path Sum | | | Solve | Easy | | |
| 116. Populating Next Right Pointers in Each Node | | | Solve | Medium | | |
| 117. Populating Next Right Pointers in Each Node II | | | Solve | Medium | | |
| 121. Best Time to Buy and Sell Stock | | | Solve | Easy | | |
| 122. Best Time to Buy and Sell Stock II | | | Solve | Medium | | |
| 134. Gas Station | | | Solve | Medium | | |
| 135. Candy | | | Solve | Hard | | |
| 138. Copy List with Random Pointer | | | Solve | Medium | | |
| 139. Word Break | | | Solve | Medium | | |
| 141. Linked List Cycle | | | Solve | Easy | 42gearMobilitySystems+131 | |
| 146. LRU Cache | | | Solve | Medium | | |
| 198. House Robber | | | Solve | Medium | | |
| 200. Number of Islands | | | Solve | Medium | | |
| 215. Kth Largest Element in an Array | | | Solve | Medium | | |
| 239. Sliding Window Maximum | | | Solve | Hard | | |
| 265. Paint House II | | | Solve | Hard | | |
| 295. Find Median from Data Stream | | | Solve | Hard | | |
| 300. Longest Increasing Subsequence | | | Solve | Medium | | |
| 355. Design Twitter | | | Solve | Medium | | |
| 373. Find K Pairs with Smallest Sums | | | Solve | Medium | | |
| 394. Decode String | | | Solve | Medium | | |
| 416. Partition Equal Subset Sum | | | Solve | Medium | | |
| 460. LFU Cache | | | Solve | Hard | | |
| 518. Coin Change II | | | Solve | Medium | | |
| 523. Continuous Subarray Sum | | | Solve | Medium | | |
| 547. Number of Provinces | | | Solve | Medium | | |
| 646. Maximum Length of Pair Chain | | | Solve | Medium | | |
| 664. Strange Printer | | | Solve | Hard | | |
| 680. Valid Palindrome II | | | Solve | Easy | | |
| 697. Degree of an Array | | | Solve | Easy | | |