| 189 | Rotate Array | Medium |
| 190 | Reverse Bits | Easy |
| 191 | Number of 1 Bits | Easy |
| 192 | Word Frequency | Medium |
| 193 | Valid Phone Numbers | Easy |
| 194 | Transpose File | Medium |
| 195 | Tenth Line | Easy |
| 196 | Delete Duplicate Emails | Easy |
| 197 | Rising Temperature | Easy |
| 198 | House Robber | Easy |
| 199 | Binary Tree Right Side View | Medium |
| 200 | Number of Islands | Medium |
| 201 | Bitwise AND of Numbers Range | Medium |
| 202 | Happy Number | Easy |
| 203 | Remove Linked List Elements | Easy |
| 204 | Count Primes | Medium |
| 205 | Isomorphic Strings | Easy |
| 206 | Reverse Linked List | Easy |
| 207 | Course Schedule | Medium |
| 208 | Implement Trie (Prefix Tree) | Medium |
| 209 | Minimum Size Subarray Sum | Medium |
| 210 | Course Schedule II | Medium |
| 211 | Design Add and Search Words Data Structure | Medium |
| 212 | Word Search II | Hard |
| 213 | House Robber II | Medium |
| 214 | Shortest Palindrome | Hard |
| 215 | Kth Largest Element in an Array | Medium |
| 216 | Combination Sum III | Medium |
| 217 | Contains Duplicate | Easy |
| 218 | The Skyline Problem | Hard |