| 806 | Number of Lines To Write String | ArrayString | Easy |
| 807 | Max Increase to Keep City Skyline | ArrayGreedyMatrix | Medium |
| 808 | Soup Servings | MathDynamic ProgrammingProbability and Statistics | Medium |
| 809 | Expressive Words | ArrayTwo PointersString | Medium |
| 810 | Chalkboard XOR Game | ArrayMathBit Manipulation+2 | Hard |
| 811 | Subdomain Visit Count | ArrayHash TableString+1 | Medium |
| 812 | Largest Triangle Area | ArrayMathGeometry | Easy |
| 813 | Largest Sum of Averages | ArrayDynamic ProgrammingPrefix Sum | Medium |
| 814 | Binary Tree Pruning | TreeDepth-First SearchBinary Tree | Medium |
| 815 | Bus Routes | ArrayHash TableBreadth-First Search | Hard |
| 816 | Ambiguous Coordinates | StringBacktrackingEnumeration | Medium |
| 817 | Linked List Components | ArrayHash TableLinked List | Medium |
| 818 | Race Car | Dynamic Programming | Hard |
| 819 | Most Common Word | ArrayHash TableString+1 | Easy |
| 820 | Short Encoding of Words | ArrayHash TableString+1 | Medium |
| 821 | Shortest Distance to a Character | ArrayTwo PointersString | Easy |
| 822 | Card Flipping Game | ArrayHash Table | Medium |
| 823 | Binary Trees With Factors | ArrayHash TableDynamic Programming+1 | Medium |
| 824 | Goat Latin | String | Easy |
| 825 | Friends Of Appropriate Ages | ArrayTwo PointersBinary Search+1 | Medium |
| 826 | Most Profit Assigning Work | ArrayTwo PointersBinary Search+2 | Medium |
| 827 | Making A Large Island | ArrayDepth-First SearchBreadth-First Search+2 | Hard |
| 828 | Count Unique Characters of All Substrings of a Given String | Hash TableStringDynamic Programming | Hard |
| 829 | Consecutive Numbers Sum | MathEnumeration | Hard |
| 830 | Positions of Large Groups | String | Easy |
| 831 | Masking Personal Information | String | Medium |
| 832 | Flipping an Image | ArrayTwo PointersBit Manipulation+2 | Easy |
| 833 | Find And Replace in String | ArrayHash TableString+1 | Medium |
| 834 | Sum of Distances in Tree | Dynamic ProgrammingTreeDepth-First Search+1 | Hard |
| 835 | Image Overlap | ArrayMatrix | Medium |
| 836 | Rectangle Overlap | MathGeometry | Easy |
| 837 | New 21 Game | MathDynamic ProgrammingSliding Window+1 | Medium |
| 838 | Push Dominoes | Two PointersStringDynamic Programming | Medium |
| 839 | Similar String Groups | ArrayHash TableString+3 | Hard |
| 840 | Magic Squares In Grid | ArrayHash TableMath+1 | Medium |
| 841 | Keys and Rooms | Depth-First SearchBreadth-First SearchGraph | Medium |
| 842 | Split Array into Fibonacci Sequence | StringBacktracking | Medium |
| 843 | Guess the Word | ArrayMathString+2 | Hard |
| 844 | Backspace String Compare | Two PointersStringStack+1 | Easy |
| 845 | Longest Mountain in Array | ArrayTwo PointersDynamic Programming+1 | Medium |
| 846 | Hand of Straights | ArrayHash TableGreedy+1 | Medium |
| 847 | Shortest Path Visiting All Nodes | Dynamic ProgrammingBit ManipulationBreadth-First Search+2 | Hard |
| 848 | Shifting Letters | ArrayStringPrefix Sum | Medium |
| 849 | Maximize Distance to Closest Person | Array | Medium |
| 850 | Rectangle Area II | ArraySegment TreeLine Sweep+1 | Hard |
| 851 | Loud and Rich | ArrayDepth-First SearchGraph+1 | Medium |
| 852 | Peak Index in a Mountain Array | ArrayBinary Search | Medium |
| 853 | Car Fleet | ArrayStackSorting+1 | Medium |
| 854 | K-Similar Strings | Hash TableStringBreadth-First Search | Hard |
| 855 | Exam Room | DesignHeap (Priority Queue)Ordered Set | Medium |