| 316 | Remove Duplicate Letters | StringStackGreedy+1 | Medium |
| 318 | Maximum Product of Word Lengths | ArrayStringBit Manipulation | Medium |
| 319 | Bulb Switcher | MathBrainteaser | Medium |
| 322 | Coin Change | ArrayDynamic ProgrammingBreadth-First Search | Medium |
| 324 | Wiggle Sort II | ArrayDivide and ConquerGreedy+2 | Medium |
| 328 | Odd Even Linked List | Linked List | Medium |
| 331 | Verify Preorder Serialization of a Binary Tree | StringStackTree+1 | Medium |
| 334 | Increasing Triplet Subsequence | ArrayGreedy | Medium |
| 337 | House Robber III | Dynamic ProgrammingTreeDepth-First Search+1 | Medium |
| 341 | Flatten Nested List Iterator | StackTreeDepth-First Search+3 | Medium |
| 343 | Integer Break | MathDynamic Programming | Medium |
| 347 | Top K Frequent Elements | ArrayHash TableDivide and Conquer+5 | Medium |
| 355 | Design Twitter | Hash TableLinked ListDesign+1 | Medium |
| 357 | Count Numbers with Unique Digits | MathDynamic ProgrammingBacktracking | Medium |
| 365 | Water and Jug Problem | MathDepth-First SearchBreadth-First Search | Medium |
| 368 | Largest Divisible Subset | ArrayMathDynamic Programming+1 | Medium |
| 371 | Sum of Two Integers | MathBit Manipulation | Medium |
| 372 | Super Pow | MathDivide and Conquer | Medium |
| 373 | Find K Pairs with Smallest Sums | ArrayHeap (Priority Queue) | Medium |
| 375 | Guess Number Higher or Lower II | MathDynamic ProgrammingGame Theory | Medium |
| 376 | Wiggle Subsequence | ArrayDynamic ProgrammingGreedy | Medium |
| 377 | Combination Sum IV | ArrayDynamic Programming | Medium |
| 378 | Kth Smallest Element in a Sorted Matrix | ArrayBinary SearchSorting+2 | Medium |
| 380 | Insert Delete GetRandom O(1) | ArrayHash TableMath+2 | Medium |
| 382 | Linked List Random Node | Linked ListMathReservoir Sampling+1 | Medium |
| 384 | Shuffle an Array | ArrayMathDesign+1 | Medium |
| 385 | Mini Parser | StringStackDepth-First Search | Medium |
| 386 | Lexicographical Numbers | Depth-First SearchTrie | Medium |
| 388 | Longest Absolute File Path | StringStackDepth-First Search | Medium |
| 390 | Elimination Game | MathRecursion | Medium |
| 393 | UTF-8 Validation | ArrayBit Manipulation | Medium |
| 394 | Decode String | StringStackRecursion | Medium |
| 395 | Longest Substring with At Least K Repeating Characters | Hash TableStringDivide and Conquer+1 | Medium |
| 396 | Rotate Function | ArrayMathDynamic Programming | Medium |
| 397 | Integer Replacement | Dynamic ProgrammingGreedyBit Manipulation+1 | Medium |
| 398 | Random Pick Index | Hash TableMathReservoir Sampling+1 | Medium |
| 399 | Evaluate Division | ArrayStringDepth-First Search+4 | Medium |
| 400 | Nth Digit | MathBinary Search | Medium |
| 402 | Remove K Digits | StringStackGreedy+1 | Medium |
| 406 | Queue Reconstruction by Height | ArrayBinary Indexed TreeSegment Tree+1 | Medium |
| 413 | Arithmetic Slices | ArrayDynamic ProgrammingSliding Window | Medium |
| 416 | Partition Equal Subset Sum | ArrayDynamic Programming | Medium |
| 417 | Pacific Atlantic Water Flow | ArrayDepth-First SearchBreadth-First Search+1 | Medium |
| 419 | Battleships in a Board | ArrayDepth-First SearchMatrix | Medium |
| 421 | Maximum XOR of Two Numbers in an Array | ArrayHash TableBit Manipulation+1 | Medium |
| 423 | Reconstruct Original Digits from English | Hash TableMathString | Medium |
| 424 | Longest Repeating Character Replacement | Hash TableStringSliding Window | Medium |
| 427 | Construct Quad Tree | ArrayDivide and ConquerTree+1 | Medium |
| 429 | N-ary Tree Level Order Traversal | TreeBreadth-First Search | Medium |
| 430 | Flatten a Multilevel Doubly Linked List | Linked ListDepth-First SearchDoubly-Linked List | Medium |