| 17. Letter Combinations of a Phone Number | | | Solve | Medium | | |
| 22. Generate Parentheses | | | Solve | Medium | | |
| 39. Combination Sum | | | Solve | Medium | | |
| 40. Combination Sum II | | | Solve | Medium | | |
| 46. Permutations | | | Solve | Medium | | |
| 47. Permutations II | | | Solve | Medium | | |
| 77. Combinations | | | Solve | Medium | | |
| 78. Subsets | | | Solve | Medium | | |
| 79. Word Search | | | Solve | Medium | | |
| 89. Gray Code | | | Solve | Medium | | |
| 90. Subsets II | | | Solve | Medium | | |
| 93. Restore IP Addresses | | | Solve | Medium | | |
| 95. Unique Binary Search Trees II | | | Solve | Medium | | |
| 113. Path Sum II | | | Solve | Medium | | |
| 131. Palindrome Partitioning | | | Solve | Medium | | |
| 216. Combination Sum III | | | Solve | Medium | | |
| 254. Factor Combinations | | | Solve | Medium | | |
| 267. Palindrome Permutation II | | | Solve | Medium | | |
| 291. Word Pattern II | | | Solve | Medium | | |
| 294. Flip Game II | | | Solve | Medium | | |
| 306. Additive Number | | | Solve | Medium | | |
| 320. Generalized Abbreviation | | | Solve | Medium | | |
| 351. Android Unlock Patterns | | | Solve | Medium | | |
| 357. Count Numbers with Unique Digits | | | Solve | Medium | | |
| 473. Matchsticks to Square | | | Solve | Medium | | |
| 491. Non-decreasing Subsequences | | | Solve | Medium | | |
| 494. Target Sum | | | Solve | Medium | | |
| 526. Beautiful Arrangement | | | Solve | Medium | | |
| 638. Shopping Offers | | | Solve | Medium | | |
| 681. Next Closest Time | | | Solve | Medium | | |
| 698. Partition to K Equal Sum Subsets | | | Solve | Medium | | |
| 784. Letter Case Permutation | | | Solve | Medium | | |
| 797. All Paths From Source to Target | | | Solve | Medium | | |
| 816. Ambiguous Coordinates | | | Solve | Medium | | |
| 842. Split Array into Fibonacci Sequence | | | Solve | Medium | | |
| 967. Numbers With Same Consecutive Differences | | | Solve | Medium | | |
| 988. Smallest String Starting From Leaf | | | Solve | Medium | | |
| 1066. Campus Bikes II | | | Solve | Medium | | |
| 1079. Letter Tile Possibilities | | | Solve | Medium | | |
| 1087. Brace Expansion | | | Solve | Medium | | |
| 1215. Stepping Numbers | | | Solve | Medium | | |
| 1219. Path with Maximum Gold | | | Solve | Medium | | |
| 1238. Circular Permutation in Binary Representation | | | Solve | Medium | | |
| 1239. Maximum Length of a Concatenated String with Unique Characters | | | Solve | Medium | | |
| 1258. Synonymous Sentences | | | Solve | Medium | | |
| 1286. Iterator for Combination | | | Solve | Medium | | |
| 1415. The k-th Lexicographical String of All Happy Strings of Length n | | | Solve | Medium | | |
| 1593. Split a String Into the Max Number of Unique Substrings | | | Solve | Medium | | |
| 1718. Construct the Lexicographically Largest Valid Sequence | | | Solve | Medium | | |
| 1774. Closest Dessert Cost | | | Solve | Medium | | |
