| 31 | Next Permutation | Medium |
| 32 | Longest Valid Parentheses | Hard |
| 33 | Search in Rotated Sorted Array | Medium |
| 34 | Find First and Last Position of Element in Sorted Array | Medium |
| 34 | Search for a Range | Medium |
| 35 | Search Insert Position | Easy |
| 36 | Valid Sudoku | Medium |
| 37 | Sudoku Solver | Hard |
| 38 | Count and Say | Easy |
| 39 | Combination Sum | Medium |
| 40 | Combination Sum II | Medium |
| 41 | First Missing Positive | Hard |
| 42 | Trapping Rain Water | Hard |
| 43 | Multiply Strings | Medium |
| 44 | Wildcard Matching | Hard |
| 45 | Jump Game II | Hard |
| 46 | Permutations | Medium |
| 47 | Permutations II | Medium |
| 48 | Rotate Image | Medium |
| 49 | Group Anagrams | Medium |
| 50 | Pow(x, n) | Medium |
| 51 | N-Queens | Hard |
| 52 | N-Queens II | Hard |
| 53 | Maximum Subarray | Easy |
| 54 | Spiral Matrix | Medium |
| 55 | Jump Game | Medium |
| 56 | Merge Intervals | Medium |
| 57 | Insert Interval | Hard |
| 58 | Length of Last Word | Easy |
| 59 | Spiral Matrix II | Medium |