poj 1961 Period（KMP）

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <string>

using namespace std;
int next[1000010];
char str[1000010];

void getnext(char *s, int len)
{
int i = 0;
int j = -1;
next[0] = -1;
while(i < len)
{
if(j == -1 || str[i] == str[j])
next[++i] = ++j;
else
j = next[j];
}
}
int main()
{
int n;
int cas = 0;
while(~scanf("%d",&n) && n)
{
scanf("%s",str);
getnext(str,n);
printf("Test case #%d\n",++cas);
for(int i=1;i<=n;i++)
{
int d = i - next[i];
if(next[i] && i % (i-next[i])== 0)
printf("%d %d\n",i, i/(i-next[i]));
} printf("\n");
}
return 0;
}