I hope my previous blog has convinced you that the best way to improve at Codeforces is to be more Russian, i.e. to improve your math capability. Unfortunately, humble mortals such as you and I are not gifted with the talent that esteemed Russian grandmasters such as 74TrAkToR had:

Surely, it is beneficial to have a code reference for many algorithms and data structures, but I also think that just superficially knowing the algorithm and maybe having implemented it once or twice before is sufficient to use it without a reference?

--- Some Codeforces grandmaster

Therefore, in this blog I will explore an alternative technique — randomly guessing — that is looked down by everyone I know. However, it has been very helpful to me, and I hope that it serves you well, too.

Example