原题链接题解首先，假设当前\(s(l,r)\)括号序列为合法序列，则有如下几种情况：\(l+1==r\)()\(match[r]==l\)(...)\(match[r]!=l\)(...)...(...)code#include<bits/stdc++.h>usingnamespacestd;constlonglongMOD=1e9+7;longlongdp[705][705][3][3]