| 826 | Most Profit Assigning Work | Medium |
| 827 | Making A Large Island | Hard |
| 828 | Count Unique Characters of All Substrings of a Given String | Hard |
| 829 | Consecutive Numbers Sum | Hard |
| 830 | Positions of Large Groups | Easy |
| 831 | Masking Personal Information | Medium |
| 832 | Flipping an Image | Easy |
| 833 | Find And Replace in String | Medium |
| 834 | Sum of Distances in Tree | Hard |
| 836 | Rectangle Overlap | Easy |
| 837 | New 21 Game | Medium |
| 838 | Push Dominoes | Medium |
| 839 | Similar String Groups | Hard |
| 840 | Magic Squares In Grid | Medium |
| 841 | Keys and Rooms | Medium |
| 842 | Split Array into Fibonacci Sequence | Medium |
| 843 | Guess the Word | Hard |
| 844 | Backspace String Compare | Easy |
| 845 | Longest Mountain in Array | Medium |
| 846 | Hand of Straights | Medium |
| 848 | Shifting Letters | Medium |
| 849 | Maximize Distance to Closest Person | Medium |
| 850 | Rectangle Area II | Hard |
| 851 | Loud and Rich | Medium |
| 852 | Peak Index in a Mountain Array | Medium |
| 853 | Car Fleet | Medium |
| 854 | K-Similar Strings | Hard |
| 855 | Exam Room | Medium |
| 856 | Score of Parentheses | Medium |
| 857 | Minimum Cost to Hire K Workers | Hard |