How is the 900 CP-31 sheet different from 800?
800 checks whether you can implement what the statement says. 900 adds a single observation — usually greedy, parity or sorting — that you have to find before the code is simple.
Priyansh Agarwal
Curated by Priyansh Agarwal, ICPC World Finalist and AIR 1 in Google Kick Start, this sheet features all essential 900-rated Codeforces questions. With a Master (India Rank 34) on Codeforces and 4000+ students taught, Priyansh’s expertise ensures that this sheet will help you sharpen your competitive programming skills and make steady progress
900 on Codeforces is Newbie level. Anyone who can clear 800 problems but still solves only one problem in a Div. 2 or Div. 3 contest.
What these problems lean on: Greedy observations, Parity and odd/even cases, Sorting, Counting, Simulation.
The usual wall at 900: 900 is where a problem first needs one small observation instead of pure implementation — noticing that only the parity matters, or that sorting makes the answer obvious.
How to practise it: Before coding, write the observation in one sentence. If you cannot, try tiny cases by hand; at this rating the pattern almost always shows up by n = 4.
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800 checks whether you can implement what the statement says. 900 adds a single observation — usually greedy, parity or sorting — that you have to find before the code is simple.
Once you can solve most of the 31 without the editorial, move on. Grinding hundreds more at the same rating gives diminishing returns.
There is no PDF here, and you do not need one. All 31 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 900 Rated: CP-31 Sheet you have actually covered. Signing in with Google syncs it across devices.
At roughly 25 minutes a problem — reading it, solving it and writing the approach down — 31 problems is about 13 hours, or 1 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 — the sheet itself is by Priyansh Agarwal, and this is a free tracker for it.
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.