I know basic combinatorics and want to get better at applying it in CP—especially in problems with constraints, DP, or number theory. I’m trying to figure out how to analyze a combinatorics problem. Any tips or practice strategies for improving this skill?
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Precompute nCr with factorial + mod inverse Stars and Bars Inclusion–Exclusion
These are the same topics our teacher taught us in Combinatorics.
You are from Pakistan,
do you have teacher btw
Yes, I do.
nice joke
wdym?
.+ computing nCr with non prime modulo
CRT is definitely worth learning too.
yes , but i think it is mainly used in high rated questions
If you don't want to use dp, or just are computing nCr with non-prime mod for really large values, than CRT can be quite efficient.
Yes they are essential. The techniques aren’t the issue for me. It’s identifying the right approach from the problem statement.
The most important thing is to practice consistently. You will naturally slowly start to understand problems.
Yes, I agree that consistent practice is important. But I’m mainly looking for specific tips on recognizing patterns and choosing the right approach in harder CP problems, especially when combinatorics interacts with constraints, DP or number theory.
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Solve AoPS questions
Thanks!
alcumus can teach you basics, then i would just do problems tagged combinatorics + dp, you should also know PIE
Thanks!