I created a video discussing strategies to upsolve and read editorials for Codeforces problems. It also talks about how to use Atcoder Library like STL, in context of problem G: Penacony from last Div 3 Round.

https://youtu.be/iMjd2QI6NEs?si=Xr9g2Mz_HTwLBLQ8

I also curated some practice problems. Here's the contest link : https://mirror.codeforces.com/group/7Dn3ObOpau/contest/538988