Hi Codeforces!

Every beginner here at least once wondered: "what to do to increase the rating?" The most common answer was to solve the archive. Immediately, the error of every newcomer surfaced: he chose the easiest tasks, solved them and did not develop at all. Or the opposite situation: He immediately took on complex tasks, did not understand anything and abandoned this business.

This is what this post was created for! What tasks do you think are the most interesting / common? What tasks should every beginner / specialist / expert solve at least once?

! [] (/ predownloaded / a6 / 27 / a627fe204e0082efe13b0a682dc6c805037019c7.png)

UPD: it is desirable that it was like in the picture: D