NOI2019考前做NOI2018题。。 题目链接: (bzoj) https://www.lydsy.com/JudgeOnline/problem.php?id=5417 (luogu) https://www.luogu.org/problemnew/show/P4770 (uoj) http://uoj.ac/problem/395 题解: 其实非常水，转化成\(S[l,r]\)和\(T