| 1177. Can Make Palindrome from Substring | | | Solve | Medium | | |
| 1181. Before and After Puzzle | | | Solve | Medium | | |
| 1190. Reverse Substrings Between Each Pair of Parentheses | | | Solve | Medium | | |
| 1202. Smallest String With Swaps | | | Solve | Medium | | |
| 1208. Get Equal Substrings Within Budget | | | Solve | Medium | | |
| 1209. Remove All Adjacent Duplicates in String II | | | Solve | Medium | | |
| 1233. Remove Sub-Folders from the Filesystem | | | Solve | Medium | | |
| 1234. Replace the Substring for Balanced String | | | Solve | Medium | | |
| 1236. Web Crawler | | | Solve | Medium | | |
| 1239. Maximum Length of a Concatenated String with Unique Characters | | | Solve | Medium | | |
| 1247. Minimum Swaps to Make Strings Equal | | | Solve | Medium | | |
| 1249. Minimum Remove to Make Valid Parentheses | | | Solve | Medium | | |
| 1256. Encode Number | | | Solve | Medium | | |
| 1257. Smallest Common Region | | | Solve | Medium | | |
| 1258. Synonymous Sentences | | | Solve | Medium | | |
| 1268. Search Suggestions System | | | Solve | Medium | | |
| 1286. Iterator for Combination | | | Solve | Medium | | |
| 1297. Maximum Number of Occurrences of a Substring | | | Solve | Medium | | |
| 1324. Print Words Vertically | | | Solve | Medium | | |
| 1328. Break a Palindrome | | | Solve | Medium | | |
| 1347. Minimum Number of Steps to Make Two Strings Anagram | | | Solve | Medium | | |
| 1358. Number of Substrings Containing All Three Characters | | | Solve | Medium | | |
| 1366. Rank Teams by Votes | | | Solve | Medium | | |
| 1371. Find the Longest Substring Containing Vowels in Even Counts | | | Solve | Medium | | |
| 1396. Design Underground System | | | Solve | Medium | | |
| 1400. Construct K Palindrome Strings | | | Solve | Medium | | |
| 1404. Number of Steps to Reduce a Number in Binary Representation to One | | | Solve | Medium | | |
| 1405. Longest Happy String | | | Solve | Medium | | |
| 1410. HTML Entity Parser | | | Solve | Medium | | |
| 1415. The k-th Lexicographical String of All Happy Strings of Length n | | | Solve | Medium | | |
| 1418. Display Table of Food Orders in a Restaurant | | | Solve | Medium | | |
| 1419. Minimum Number of Frogs Croaking | | | Solve | Medium | | |
| 1433. Check If a String Can Break Another String | | | Solve | Medium | | |
| 1447. Simplified Fractions | | | Solve | Medium | | |
| 1451. Rearrange Words in a Sentence | | | Solve | Medium | | |
| 1452. People Whose List of Favorite Companies Is Not a Subset of Another List | | | Solve | Medium | | |
| 1456. Maximum Number of Vowels in a Substring of Given Length | | | Solve | Medium | | |
| 1461. Check If a String Contains All Binary Codes of Size K | | | Solve | Medium | | |
| 1487. Making File Names Unique | | | Solve | Medium | | |
| 1513. Number of Substrings With Only 1s | | | Solve | Medium | | |
| 1525. Number of Good Ways to Split a String | | | Solve | Medium | | |
| 1529. Minimum Suffix Flips | | | Solve | Medium | | |
| 1540. Can Convert String in K Moves | | | Solve | Medium | | |
| 1541. Minimum Insertions to Balance a Parentheses String | | | Solve | Medium | | |
| 1545. Find Kth Bit in Nth Binary String | | | Solve | Medium | | |
| 1554. Strings Differ by One Character | | | Solve | Medium | | |
| 1573. Number of Ways to Split a String | | | Solve | Medium | | |
| 1578. Minimum Time to Make Rope Colorful | | | Solve | Medium | | |
| 1593. Split a String Into the Max Number of Unique Substrings | | | Solve | Medium | | |
| 1604. Alert Using Same Key-Card Three or More Times in a One Hour Period | | | Solve | Medium | | |
