| 201 | Bitwise AND of Numbers Range | Medium | 1604 | bit-manipulation |
| 204 | Count Primes | Medium | 1500 | matharraysieve-of-eratosthenes |
| 207 | Course Schedule | Medium | 1656 | depth-first-searchbreadth-first-searchgraph+1 |
| 208 | Implement Trie (Prefix Tree) | Medium | 1543 | hash-tablestringdesign+1 |
| 209 | Minimum Size Subarray Sum | Medium | 1445 | arraybinary-searchsliding-window+1 |
| 210 | Course Schedule II | Medium | 1681 | depth-first-searchbreadth-first-searchgraph+1 |
| 211 | Design Add and Search Words Data Structure | Medium | 1758 | stringdepth-first-searchdesign+1 |
| 213 | House Robber II | Medium | 1608 | arraydynamic-programming |
| 215 | Kth Largest Element in an Array | Medium | 1508 | arraydivide-and-conquersorting+2 |
| 216 | Combination Sum III | Medium | 1460 | backtrackingarray |
| 221 | Maximal Square | Medium | 1638 | arraydynamic-programmingmatrix |
| 230 | Kth Smallest Element in a BST | Medium | 1401 | treedepth-first-searchbinary-search-tree+1 |
| 235 | Lowest Common Ancestor of a Binary Search Tree | Medium | 1333 | treedepth-first-searchbinary-search-tree+1 |
| 236 | Lowest Common Ancestor of a Binary Tree | Medium | 1660 | treedepth-first-searchbinary-tree |
| 237 | Delete Node in a Linked List | Medium | 1300 | linked-list |
| 238 | Product of Array Except Self | Medium | 1480 | arrayprefix-sum |
| 240 | Search a 2D Matrix II | Medium | 1499 | arraybinary-searchdivide-and-conquer+1 |
| 253 | Meeting Rooms II | Medium | 1582 | arraytwo-pointersgreedy+3 |
| 256 | Paint House | Medium | — | arraydynamic-programming |
| 260 | Single Number III | Medium | 1321 | arraybit-manipulation |
| 261 | Graph Valid Tree | Medium | 1620 | depth-first-searchbreadth-first-searchunion-find+1 |
| 264 | Ugly Number II | Medium | 1559 | dynamic-programmingmathheap-priority-queue |
| 271 | Encode and Decode Strings | Medium | 1530 | arraystringdesign |
| 274 | H-Index | Medium | 1405 | arraysortingcounting-sort |
| 279 | Perfect Squares | Medium | 1529 | mathdynamic-programmingbreadth-first-search |
| 280 | Wiggle Sort | Medium | — | arraygreedysorting |
| 286 | Walls and Gates | Medium | 1638 | arraybreadth-first-searchmatrix |
| 287 | Find the Duplicate Number | Medium | 1689 | arraytwo-pointersbinary-search+1 |
| 289 | Game of Life | Medium | 1529 | arraymatrixsimulation |
| 300 | Longest Increasing Subsequence | Medium | 1666 | arraybinary-searchdynamic-programming |
| 304 | Range Sum Query 2D - Immutable | Medium | 1408 | arraydesignmatrix+1 |
| 307 | Range Sum Query - Mutable | Medium | — | arraydivide-and-conquerdesign+2 |
| 309 | Best Time to Buy and Sell Stock with Cooldown | Medium | 1708 | arraydynamic-programming |
| 310 | Minimum Height Trees | Medium | 1657 | treedepth-first-searchbreadth-first-search+2 |
| 314 | Binary Tree Vertical Order Traversal | Medium | — | treebreadth-first-searchhash-table |
| 316 | Remove Duplicate Letters | Medium | 1568 | stringgreedystack+1 |
| 322 | Coin Change | Medium | 1684 | arraydynamic-programmingbreadth-first-search |
| 323 | Number of Connected Components in an Undirected Graph | Medium | 1558 | depth-first-searchbreadth-first-searchunion-find+1 |
| 328 | Odd Even Linked List | Medium | 1360 | linked-listtwo-pointers |
| 334 | Increasing Triplet Subsequence | Medium | — | arraygreedy |
| 337 | House Robber III | Medium | — | dynamic-programmingtreedepth-first-search+1 |
| 340 | Longest Substring with At Most K Distinct Characters | Medium | 1679 | hash-tablestringsliding-window |
| 341 | Flatten Nested List Iterator | Medium | — | stacktreedepth-first-search+3 |
| 343 | Integer Break | Medium | — | mathdynamic-programming |
| 347 | Top K Frequent Elements | Medium | 1540 | arrayhash-tabledivide-and-conquer+5 |
| 355 | Design Twitter | Medium | 1479 | hash-tablelinked-listdesign+1 |
| 370 | Range Addition | Medium | 1607 | arrayprefix-sum |
| 371 | Sum of Two Integers | Medium | 1564 | mathbit-manipulation |
| 373 | Find K Pairs with Smallest Sums | Medium | 1710 | arrayheap-priority-queue |
| 375 | Guess Number Higher or Lower II | Medium | — | mathdynamic-programminggame-theory |