| 10 | Regular Expression Matching | Hard |
| 17 | Letter Combinations of a Phone Number | Medium |
| 22 | Generate Parentheses | Medium |
| 37 | Sudoku Solver | Hard |
| 39 | Combination Sum | Medium |
| 40 | Combination Sum II | Medium |
| 44 | Wildcard Matching | Hard |
| 46 | Permutations | Medium |
| 47 | Permutations II | Medium |
| 51 | N-Queens | Hard |
| 52 | N-Queens II | Hard |
| 60 | Permutation Sequence | Medium |
| 77 | Combinations | Medium |
| 78 | Subsets | Medium |
| 79 | Word Search | Medium |
| 89 | Gray Code | Medium |
| 90 | Subsets II | Medium |
| 93 | Restore IP Addresses | Medium |
| 126 | Word Ladder II | Hard |
| 131 | Palindrome Partitioning | Medium |
| 140 | Word Break II | Hard |
| 401 | Binary Watch | Easy |
| 967 | Numbers With Same Consecutive Differences | Medium |
| 980 | Unique Paths III | Hard |
| 1239 | Maximum Length of a Concatenated String with Unique Characters | Medium |
| 1601 | Maximum Number of Achievable Transfer Requests | Hard |
| 1718 | Construct the Lexicographically Largest Valid Sequence | Medium |
| 1774 | Closest Dessert Cost | Medium |
| 1980 | Find Unique Binary String | Medium |
| 2305 | Fair Distribution of Cookies | Medium |