| 831 | Masking Personal Information | Medium |
| 833 | Find And Replace in String | Medium |
| 838 | Push Dominoes | Medium |
| 839 | Similar String Groups | Hard |
| 842 | Split Array into Fibonacci Sequence | Medium |
| 843 | Guess the Word | Hard |
| 844 | Backspace String Compare | Easy |
| 848 | Shifting Letters | Medium |
| 854 | K-Similar Strings | Hard |
| 856 | Score of Parentheses | Medium |
| 859 | Buddy Strings | Easy |
| 880 | Decoded String at Index | Medium |
| 884 | Uncommon Words from Two Sentences | Easy |
| 890 | Find and Replace Pattern | Medium |
| 893 | Groups of Special-Equivalent Strings | Medium |
| 899 | Orderly Queue | Hard |
| 916 | Word Subsets | Medium |
| 917 | Reverse Only Letters | Easy |
| 921 | Minimum Add to Make Parentheses Valid | Medium |
| 925 | Long Pressed Name | Easy |
| 926 | Flip String to Monotone Increasing | Medium |
| 929 | Unique Email Addresses | Easy |
| 936 | Stamping The Sequence | Hard |
| 937 | Reorder Data in Log Files | Medium |
| 940 | Distinct Subsequences II | Hard |
| 942 | DI String Match | Easy |
| 943 | Find the Shortest Superstring | Hard |
| 944 | Delete Columns to Make Sorted | Easy |
| 949 | Largest Time for Given Digits | Medium |
| 953 | Verifying an Alien Dictionary | Easy |