poj 1961 Period

http://poj.org/problem?id=1961

此题直接上代码：

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<cmath>
#include<queue>
#include<algorithm>
#include<set>

using namespace std;

const int N=1000010;

char s[N];
int next[N];
int ans[N];
void findnext(int n)
{
    int j=-1;
    int i=0;
    next[0]=-1;
    while(i<n)
    {
        if(j==-1||s[i]==s[j])
        {
            ++j;++i;next[i]=j;
        }else
        {
            j=next[j];
        }
    }
}
int main()
{

   int n;
   int w=0;
   while(scanf("%d",&n)!=EOF,n)
   {
       ++w;
       getchar();
       gets(s);
       findnext(n);
       printf("Test case #%d\n",w);
       for(int i=2;i<=n;++i)
       {
           int l=i-next[i];
           if(next[i]>=i/2&&i%l==0)
           {
               printf("%d %d\n",i,i/l);
           }
       }
       printf("\n");
   }
   return 0;
}