First 3 problems were kinda easy. Grime Zoo also felt easy at first. Quickly wrote a quick DP solution and only 40 minutes after the match I finished debugging the last bug. When problem is all about 01 you have many places for off by one mistakes. I must practice more. The general idea was simple, at any specific point in string you have given number of question marks. Any fraction of them could be used as 1s. So you store the lowest number of comments obtainable for each number of 1s and advance from there.