Curated from a highly upvoted LeetCode blog post, this sheet covers essential string problem patterns supported by the coder community. String problems can often feel unpredictable due to the variety of approaches involved, but this collection will help you recognize and apply key patterns effectively. By working through these questions, you’ll gain the confidence to tackle any string problem with the right approach.
0%
0/51
Overall progress
0 / 51
0/16
Easy
0/23
Medium
0/12
Hard
There is no PDF here, and you do not need one. All 51 problems are listed in full on this page, free and without an account — and unlike a PDF the list remembers what you have ticked off, so you are not re-reading a static file to work out where you stopped. Use your browser's print view if you want it on paper.
Tick a problem on this page and it stays ticked. Progress saves in your browser straight away with no account, and the counts update per section so you can see which parts of String Mastery Sheet you have actually covered. Signing in with Google syncs it across devices.
51, grouped into 6 topics. Every one is listed on this page and tickable as you solve it.
At roughly 25 minutes a problem — reading it, solving it and writing the approach down — 51 problems is about 21 hours, or 2 weeks at ten hours a week. Treat that as a planning figure rather than a promise; the first pass through an unfamiliar topic is always slower.
Yes, completely, and no account is needed. There is no paid tier and nothing is held back.
Finish one. Sheets overlap heavily, so working several in parallel mostly means re-solving the same problems while never completing a full topic sweep. If you are not sure this is the right one for the time you have, the sheet comparison page puts the options side by side with hour estimates.