| 856 | Score of Parentheses | StringStack | Medium |
| 857 | Minimum Cost to Hire K Workers | ArrayGreedySorting+1 | Hard |
| 858 | Mirror Reflection | MathGeometryNumber Theory | Medium |
| 859 | Buddy Strings | Hash TableString | Easy |
| 860 | Lemonade Change | ArrayGreedy | Easy |
| 861 | Score After Flipping Matrix | ArrayGreedyBit Manipulation+1 | Medium |
| 862 | Shortest Subarray with Sum at Least K | ArrayBinary SearchQueue+4 | Hard |
| 863 | All Nodes Distance K in Binary Tree | Hash TableTreeDepth-First Search+2 | Medium |
| 864 | Shortest Path to Get All Keys | ArrayBit ManipulationBreadth-First Search+1 | Hard |
| 865 | Smallest Subtree with all the Deepest Nodes | Hash TableTreeDepth-First Search+2 | Medium |
| 866 | Prime Palindrome | MathNumber Theory | Medium |
| 867 | Transpose Matrix | ArrayMatrixSimulation | Easy |
| 868 | Binary Gap | Bit Manipulation | Easy |
| 869 | Reordered Power of 2 | Hash TableMathSorting+2 | Medium |
| 870 | Advantage Shuffle | ArrayTwo PointersGreedy+1 | Medium |
| 871 | Minimum Number of Refueling Stops | ArrayDynamic ProgrammingGreedy+1 | Hard |
| 872 | Leaf-Similar Trees | TreeDepth-First SearchBinary Tree | Easy |
| 873 | Length of Longest Fibonacci Subsequence | ArrayHash TableDynamic Programming | Medium |
| 874 | Walking Robot Simulation | ArrayHash TableSimulation | Medium |
| 875 | Koko Eating Bananas | ArrayBinary Search | Medium |
| 876 | Middle of the Linked List | Linked ListTwo Pointers | Easy |
| 877 | Stone Game | ArrayMathDynamic Programming+1 | Medium |
| 878 | Nth Magical Number | MathBinary Search | Hard |
| 879 | Profitable Schemes | ArrayDynamic Programming | Hard |
| 880 | Decoded String at Index | StringStack | Medium |
| 881 | Boats to Save People | ArrayTwo PointersGreedy+1 | Medium |
| 882 | Reachable Nodes In Subdivided Graph | GraphHeap (Priority Queue)Shortest Path | Hard |
| 883 | Projection Area of 3D Shapes | ArrayMathGeometry+1 | Easy |
| 884 | Uncommon Words from Two Sentences | Hash TableStringCounting | Easy |
| 885 | Spiral Matrix III | ArrayMatrixSimulation | Medium |
| 886 | Possible Bipartition | Depth-First SearchBreadth-First SearchUnion Find+1 | Medium |
| 887 | Super Egg Drop | MathBinary SearchDynamic Programming | Hard |
| 888 | Fair Candy Swap | ArrayHash TableBinary Search+1 | Easy |
| 889 | Construct Binary Tree from Preorder and Postorder Traversal | ArrayHash TableDivide and Conquer+2 | Medium |
| 890 | Find and Replace Pattern | ArrayHash TableString | Medium |
| 891 | Sum of Subsequence Widths | ArrayMathSorting | Hard |
| 892 | Surface Area of 3D Shapes | ArrayMathGeometry+1 | Easy |
| 893 | Groups of Special-Equivalent Strings | ArrayHash TableString+1 | Medium |
| 894 | All Possible Full Binary Trees | Dynamic ProgrammingTreeRecursion+2 | Medium |
| 895 | Maximum Frequency Stack | Hash TableStackDesign+1 | Hard |
| 896 | Monotonic Array | Array | Easy |
| 897 | Increasing Order Search Tree | StackTreeDepth-First Search+2 | Easy |
| 898 | Bitwise ORs of Subarrays | ArrayDynamic ProgrammingBit Manipulation | Medium |
| 899 | Orderly Queue | MathStringSorting | Hard |
| 900 | RLE Iterator | ArrayDesignCounting+1 | Medium |
| 901 | Online Stock Span | StackDesignMonotonic Stack+1 | Medium |
| 902 | Numbers At Most N Given Digit Set | ArrayMathString+2 | Hard |
| 903 | Valid Permutations for DI Sequence | StringDynamic ProgrammingPrefix Sum | Hard |
| 904 | Fruit Into Baskets | ArrayHash TableSliding Window | Medium |
| 905 | Sort Array By Parity | ArrayTwo PointersSorting | Easy |