| 208 | Implement Trie (Prefix Tree) | Medium | tree |
| 211 | Add and Search Word - Data structure design | Medium | tree |
| 212 | Word Search II | Hard | backtracking |
| 421 | Maximum XOR of Two Numbers in an Array | Medium | bit manipulation |
| 648 | Replace Words | Medium | string |
| 676 | Implement Magic Dictionary | Medium | backtracking |
| 677 | Map Sum Pairs | Medium | tree |
| 720 | Longest Word in Dictionary | Easy | string |
| 745 | Prefix and Suffix Search | Hard | design |
| 820 | Short Encoding of Words | Medium | string |
| 1032 | Stream of Characters | Hard | tree |
| 1065 | Index Pairs of a String | Easy | tree |
| 1178 | Number of Valid Words for Each Puzzle | Hard | string |
| 1233 | Remove Sub-Folders from the Filesystem | Medium | string |
| 1268 | Search Suggestions System | Medium | design |
| 1408 | String Matching in an Array | Easy | string |
| 1410 | HTML Entity Parser | Medium | string |
| 1698 | Number of Distinct Substrings in a String | Medium | string |
| 1707 | Maximum XOR With an Element From Array | Hard | bit manipulation |
| 1803 | Count Pairs With XOR in a Range | Hard | dynamic programming |
| 1804 | Implement Trie II (Prefix Tree) | Medium | design |
| 1858 | Longest Word With All Prefixes | Medium | string |
| 1938 | Maximum Genetic Difference Query | Hard | tree |
| 1948 | Delete Duplicate Folders in System | Hard | tree |
| 1967 | Number of Strings That Appear as Substrings in Word | Easy | string |
| 2261 | K Divisible Elements Subarrays | Medium | hash table |
| 2416 | Sum of Prefix Scores of Strings | Hard | string |
| 2479 | Maximum XOR of Two Non-Overlapping Subtrees | Hard | greedy |
| 2630 | Memoize II | Hard | design |
| 2707 | Extra Characters in a String | Medium | dynamic programming |
| 2781 | Length of the Longest Valid Substring | Hard | two pointers |
| 2932 | Maximum Strong Pair XOR I | Easy | bit manipulation |
| 2935 | Maximum Strong Pair XOR II | Hard | bit manipulation |
| 2977 | Minimum Cost to Convert String II | Hard | dynamic programming |
| 3042 | Count Prefix and Suffix Pairs I | Easy | string |
| 3043 | Find the Length of the Longest Common Prefix | Medium | string |
| 3045 | Count Prefix and Suffix Pairs II | Hard | string |
| 3076 | Shortest Uncommon Substring in an Array | Medium | string |
| 3093 | Longest Common Suffix Queries | Hard | string |
| 3213 | Construct String with Minimum Cost | Hard | dynamic programming |
| 3253 | Construct String with Minimum Cost (Easy) | Medium | dynamic programming |
| 3291 | Minimum Number of Valid Strings to Form Target I | Medium | dynamic programming |
| 3292 | Minimum Number of Valid Strings to Form Target II | Hard | dynamic programming |
| 3485 | Longest Common Prefix of K Strings After Removal | Hard | two pointers |
| 3491 | Phone Number Prefix | Easy | string |
| 3597 | Partition String | Medium | simulation |
| 3632 | Subarrays with XOR at Least K | Hard | bit manipulation |
| 3845 | Maximum Subarray XOR with Bounded Range | Hard | two pointers |