I know that usaco guide classifies problems based on difficulty. I was wondering for a typical bronze contest, are the problems random in terms of difficulty? Sometimes I encounter two problems in the same contest that are very easy and sometimes I don’t. Is each contest pretty “equal” in difficulty or is it possible to get lucky on some contests and get easy questions? Specifically, is there a rough estimate in percentage for the occurrence of “easy”, “medium”, “very hard” problems?
From my experience, contests can vary wildly in difficulty. Some might consist entirely of easy problems, and some might have really hard problems. Because of this, the cutoff is different for each contest.