| 184. Department Highest Salary | | | Solve | Medium | | |
| 187. Repeated DNA Sequences | | | Solve | Medium | | |
| 189. Rotate Array | | | Solve | Medium | | |
| 198. House Robber | | | Solve | Medium | | |
| 199. Binary Tree Right Side View | | | Solve | Medium | | |
| 200. Number of Islands | | | Solve | Medium | | |
| 204. Count Primes | | | Solve | Medium | | |
| 207. Course Schedule | | | Solve | Medium | | |
| 208. Implement Trie (Prefix Tree) | | | Solve | Medium | | |
| 209. Minimum Size Subarray Sum | | | Solve | Medium | | |
| 210. Course Schedule II | | | Solve | Medium | | |
| 211. Design Add and Search Words Data Structure | | | Solve | Medium | | |
| 213. House Robber II | | | Solve | Medium | | |
| 215. Kth Largest Element in an Array | | | Solve | Medium | | |
| 221. Maximal Square | | | Solve | Medium | | |
| 223. Rectangle Area | | | Solve | Medium | | |
| 227. Basic Calculator II | | | Solve | Medium | | |
| 229. Majority Element II | | | Solve | Medium | | |
| 230. Kth Smallest Element in a BST | | | Solve | Medium | | |
| 235. Lowest Common Ancestor of a Binary Search Tree | | | Solve | Medium | | |
| 236. Lowest Common Ancestor of a Binary Tree | | | Solve | Medium | | |
| 237. Delete Node in a Linked List | | | Solve | Medium | | |
| 238. Product of Array Except Self | | | Solve | Medium | | |
| 240. Search a 2D Matrix II | | | Solve | Medium | | |
| 245. Shortest Word Distance III | | | Solve | Medium | | |
| 253. Meeting Rooms II | | | Solve | Medium | | |
| 256. Paint House | | | Solve | Medium | | |
| 261. Graph Valid Tree | | | Solve | Medium | | |
| 274. H-Index | | | Solve | Medium | | |
| 277. Find the Celebrity | | | Solve | Medium | | |
| 279. Perfect Squares | | | Solve | Medium | | |
| 280. Wiggle Sort | | | Solve | Medium | | |
| 281. Zigzag Iterator | | | Solve | Medium | | |
| 284. Peeking Iterator | | | Solve | Medium | | |
| 286. Walls and Gates | | | Solve | Medium | | |
| 287. Find the Duplicate Number | | | Solve | Medium | | |
| 289. Game of Life | | | Solve | Medium | | |
| 298. Binary Tree Longest Consecutive Sequence | | | Solve | Medium | | |
| 300. Longest Increasing Subsequence | | | Solve | Medium | | |
| 304. Range Sum Query 2D - Immutable | | | Solve | Medium | | |
| 307. Range Sum Query - Mutable | | | Solve | Medium | | |
| 309. Best Time to Buy and Sell Stock with Cooldown | | | Solve | Medium | | |
| 310. Minimum Height Trees | | | Solve | Medium | | |
| 311. Sparse Matrix Multiplication | | | Solve | Medium | | |
| 314. Binary Tree Vertical Order Traversal | | | Solve | Medium | | |
| 316. Remove Duplicate Letters | | | Solve | Medium | | |
| 322. Coin Change | | | Solve | Medium | | |
| 323. Number of Connected Components in an Undirected Graph | | | Solve | Medium | | |
| 325. Maximum Size Subarray Sum Equals k | | | Solve | Medium | | |
| 328. Odd Even Linked List | | | Solve | Medium | | |
