poj 1961 Period

#include<cstdio>
#include<cstring>
#include<iostream>
using namespace std;
int n,t;
char s[1000001];
int f[1000010];
void getnext()
{
    for(int i=1;i<n;i++)
    {
        int j=f[i];
        while(j&&s[i]!=s[j]) j=f[j];
        f[i+1]= s[i]==s[j] ? j+1:0;
        if(i>=1&&f[i+1])
        {
            int a=i+1-f[i+1];
            if((i+1)%a==0) printf("%d %d\n",i+1,(i+1)/a);
        }
    }
}
int main()
{
    while(scanf("%d",&n)!=EOF)
    {
            t++;
            if(!n) return 0;
            scanf("%s",s);
            memset(f,0,sizeof(f));
            printf("Test case #%d\n",t);
            getnext();
            printf("\n");
    }    
}