洛谷 P4391 [BOI2009]Radio Transmission 无线传输

题目传送门

解题思路:

本题所要求的循环节,其实就是最长公共前缀的前缀长度减去前后缀重叠的一部分

AC代码:

 #include<iostream>
 #include<cstdio>

 using namespace std;

 int n,j,next[];
 string l,p; 

 int main() {
     scanf("%d",&n);
     l = " ";
     cin >> p;
     l += p;
     next[] = ;
     for(int i = ;i <= n; i++) {
         while(j !=  && l[i] != l[j+]) j = next[j];
         if(l[i] == l[j+]) j++;
         next[i] = j;
     }
     printf("%d",n - next[n]);
     return ;
 }