求最循环节的个数：

#include "iostream"
#include "algorithm"
#include "cstring"
#include "cstdio"
#include "iomanip"
using namespace std;
string  a;
int nextt[100005];

void getnext(){
    int i=0,j=-1;
    nextt[0]=-1;
    while(i<a.length()){
        if(j==-1||a[i]==a[j]){
            i++;
            j++;
            nextt[i]=j;
        }
        else
            j=nextt[j];
    }
}

int main(){
    std::ios::sync_with_stdio(false);
    int T,n,m;
    cin>>T;
    while(T--){
        cin>>a;
        getnext();
        int n=a.length()-nextt[a.length()];//循环节长度
        int m=a.length();
        if(n!=m&&m%n==0)printf("0\n");//如果可以多次循环
        else printf("%d\n",n-nextt[m]%n);//取余的作用：abcab，去掉abc
    }
    return 0;
}

附：求最大的循环节的个数

int ans = 1;
int l=s.length();
if(l%(l-nextt[l])==0)
      ans=l/(l-nextt[l]);
cout<<ans<<endl;