[AcWing 1052] 设计密码

KMP + 状态机

点击查看代码[code]#include#include#include#includeusing namespace std;const int N = 60;const int mod = 1e9 + 7;int n;char str[N];int ne[N];int f[N][N];int main(){    cin >> n >> str + 1;    int m = strlen(str + 1);    for (int i = 2, j = 0; i