English version is in beta. All contents of the site should be already translated (mostly using machine translation), and everything should work properly. However, if you find any problems, please contact me.

Level 10A

To advance to the next level, you need to solve all problems.

Cartesian tree with implicit key

Theory on e-maxx
Theory on habr
I think a lot of other things are easily searched for on the Internet

Advanced number theory, Chinese remainder theorem

Inclusion-exclusion formula