I struggle to even understand those problems, I checked a lot of 1000-1200 graphs tasks, and I just don't understand them. https://mirror.codeforces.com/problemset/problem/2078/B

and the solution for that issue it is not understable for me.

https://mirror.codeforces.com/problemset/problem/217/A

A lot of the times, I read the problem, I don't understand fully the problem, the only problem I solved in that range is this one. not sure why it is 1100 https://mirror.codeforces.com/contest/1829/problem/E