| # | Title | Language | Difficulty |
|---|---|---|---|
| 1 | Two Sum | Java | Easy |
| 10 | Regular Expression Matching | Scala, C | Hard |
| 130 | Surrounded Regions | Java | Medium |
| 136 | Single Number | Java | Easy |
| 146 | LRU Cache | Scala | Hard |
| 149 | Max Points on a Line | Scala | Hard |
| 151 | Reverse Words in a String | Java | Medium |
| 189 | Rotate Array | Java | Easy |
| 198 | House Robber | Java | Easy |
| 20 | Valid Parentheses | Scala | Easy |
| 200 | Number of Islands | Java | Medium |
| 217 | Contains Duplicate | Java | Easy |
| 257 | Binary Tree Paths | Scala | Easy |
| 26 | Remove Duplicates from Sorted Array | Java | Easy |
| 297 | Serialize and Deserialize Binary Tree | Java, C | Hard |
| 322 | Coin Change | Scala | Medium |
| 44 | Wildcard Matching | Scala | Hard |
| 56 | Merge Intervals | Java | Medium |
| 565 | Array Nesting | Scala | Medium |
| 598 | Range Addition II | Scala | Easy |
| 599 | Minimum Index Sum of Two Lists | Scala | Easy |
| 695 | Max Area of Island | Java | Medium |
| 717 | 1-bit and 2-bit Characters | Java | Easy |
| 8 | String to Integer (atoi) | Scala | Medium |
| 2 | Add Two Numbers | Java | Medium |
| 82 | Remove Duplicates from Sorted List II | Java | Medium |
| 19 | Remove Nth Node From End of List | Java | Medium |
| 23 | Merge k Sorted Lists | Java | Hard |
| 25 | Reverse Nodes in k-Group | Java | Hard |
| 338 | Counting Bits | Java | Medium |
| 213 | House Robber II | Java | Medium |
| 1038 | Binary Search Tree to Greater Sum Tree | Java | Medium |
| 1003 | Check If Word Is Valid After Substitutions | Java | Medium |
| 64 | Minimum Path Sum | Java | Medium |
| 1233 | Remove Sub-Folders from the Filesystem | Java | Medium |
| 139 | Word Break | Java | Medium |