【Codeforces Round 334 (Div 2)C】【腦洞】Alternative Thinking 最多反轉一個區間使得最長跳躍子串的長度儘可能長
Kevin has just recevied his disappointing results on the USA Identification of Cows Olympiad (USAICO) in the form of a binary string of lengthn. Each character of Kevin's string represents Kevin's score on one of thenquestions of the olympiad—'1'for a correctly identified cow and'0'otherwise.
However, all is not lost. Kevin is a big proponent of alternative thinking and believes that his score, instead of being the sum of his points, should be the length of the longest alternating subsequence of his string. Here, we define analternating subsequence
Kevin, being the sneaky little puffball that he is, is willing to hack into the USAICO databases to improve his score. In order to be subtle, he decides that he will flip exactly one substring—that is, take acontiguous