| 621 | Task Scheduler | Medium | 1667 | arrayhash-tablegreedy+3 |
| 622 | Design Circular Queue | Medium | — | arraylinked-listdesign+1 |
| 641 | Design Circular Deque | Medium | — | arraylinked-listdesign+1 |
| 646 | Maximum Length of Pair Chain | Medium | 1544 | arraydynamic-programminggreedy+1 |
| 647 | Palindromic Substrings | Medium | 1525 | two-pointersstringdynamic-programming |
| 648 | Replace Words | Medium | 1410 | triehash-tablestring |
| 649 | Dota2 Senate | Medium | 1530 | queuegreedy |
| 652 | Find Duplicate Subtrees | Medium | — | hash-tabletreedepth-first-search+1 |
| 654 | Maximum Binary Tree | Medium | — | arraydivide-and-conquerstack+3 |
| 658 | Find K Closest Elements | Medium | 1702 | arraytwo-pointersbinary-search+2 |
| 662 | Maximum Width of Binary Tree | Medium | — | treedepth-first-searchbreadth-first-search+1 |
| 665 | Non-decreasing Array | Medium | — | array |
| 669 | Trim a Binary Search Tree | Medium | — | treedepth-first-searchbinary-search-tree+1 |
| 673 | Number of Longest Increasing Subsequence | Medium | — | arraydynamic-programmingbinary-indexed-tree+1 |
| 676 | Implement Magic Dictionary | Medium | 1480 | hash-tablestringdepth-first-search+1 |
| 677 | Map Sum Pairs | Medium | 1445 | triehash-tabledesign |
| 678 | Valid Parenthesis String | Medium | 1700 | stringdynamic-programmingstack+1 |
| 684 | Redundant Connection | Medium | 1597 | depth-first-searchbreadth-first-searchunion-find+1 |
| 686 | Repeated String Match | Medium | — | stringstring-matching |
| 692 | Top K Frequent Words | Medium | — | arrayhash-tablestring+5 |
| 695 | Max Area of Island | Medium | 1470 | arraydepth-first-searchbreadth-first-search+2 |
| 698 | Partition to K Equal Sum Subsets | Medium | 1677 | backtrackingbit-manipulationdynamic-programming |
| 701 | Insert into a Binary Search Tree | Medium | — | treebinary-search-treebinary-tree |
| 707 | Design Linked List | Medium | — | linked-listdesign |
| 713 | Subarray Product Less Than K | Medium | 1539 | arraysliding-windowprefix-sum |
| 714 | Best Time to Buy and Sell Stock with Transaction Fee | Medium | 1675 | dynamic-programminggreedyarray |
| 720 | Longest Word in Dictionary | Medium | 1355 | triehash-tablesorting+1 |
| 721 | Accounts Merge | Medium | 1664 | arrayhash-tablestring+4 |
| 725 | Split Linked List in Parts | Medium | — | linked-list |
| 729 | My Calendar I | Medium | — | arraybinary-searchdesign+2 |
| 731 | My Calendar II | Medium | — | arraybinary-searchdesign+3 |
| 735 | Asteroid Collision | Medium | 1550 | stackarraysimulation |
| 739 | Daily Temperatures | Medium | 1418 | arraystackmonotonic-stack |
| 740 | Delete and Earn | Medium | — | arrayhash-tabledynamic-programming |
| 743 | Network Delay Time | Medium | 1648 | depth-first-searchbreadth-first-searchgraph+2 |
| 752 | Open the Lock | Medium | 1878 | arrayhash-tablestring+1 |
| 763 | Partition Labels | Medium | 1464 | hash-tabletwo-pointersstring+1 |
| 767 | Reorganize String | Medium | 1681 | hash-tablestringgreedy+3 |
| 785 | Is Graph Bipartite? | Medium | 1625 | depth-first-searchbreadth-first-searchunion-find+1 |
| 786 | K-th Smallest Prime Fraction | Medium | 1818 | arraytwo-pointersbinary-search+2 |
| 787 | Cheapest Flights Within K Stops | Medium | 1786 | dynamic-programmingdepth-first-searchbreadth-first-search+3 |
| 790 | Domino and Tromino Tiling | Medium | 1796 | dynamic-programmingmath |
| 795 | Number of Subarrays with Bounded Maximum | Medium | 1817 | arraytwo-pointersprefix-sum |
| 797 | All Paths From Source to Target | Medium | 1383 | backtrackingdepth-first-searchbreadth-first-search+1 |
| 802 | Find Eventual Safe States | Medium | 1962 | depth-first-searchbreadth-first-searchgraph+1 |
| 820 | Short Encoding of Words | Medium | 1623 | arrayhash-tablestring+1 |
| 837 | New 21 Game | Medium | 2350 | mathdynamic-programmingsliding-window+1 |
| 838 | Push Dominoes | Medium | 1638 | two-pointersstringdynamic-programming |
| 841 | Keys and Rooms | Medium | 1412 | depth-first-searchbreadth-first-searchgraph |
| 846 | Hand of Straights | Medium | 1604 | arrayhash-tablegreedy+1 |