http://acm.hdu.edu.cn/showproblem.php?pid=1358
#include<iostream>
#include<string.h>
using namespace std;
#define M 1000005
int next[M];
char s[M];
void getnext()
{
int i=0,j=-1;
next[0]=-1;
int len=strlen(s);
while(i<len)
{
if(j==-1||s[i]==s[j])
{
i++;
j++;
next[i]=j;
}
else
j=next[j];
}
}
int main()
{
int text=0,n;
while(scanf("%d",&n)>0&&n)
{
scanf("%s",s);
getnext();
printf("Test case #%d\n",++text);
int i,j=0;
int len=strlen(s);
for(i=1;i<len;i++)
{
if(next[i+1]!=0&&(i+1)%(i+1-next[i+1])==0)
{
printf("%d %d\n",i+1,(i+1)/(i+1-next[i+1]));
}
}
printf("\n");
}
return 0;
}