Power Strings POJ - 2406,字符串hash

//#include<bits/stdc++.h>
#include<iostream>
#include<cstdio>
#include<string>
#include<cstring>
#include<algorithm>
#define pb push_back
#define ll long long
#define ull unsigned long long
#define rank wepsdas
#define PI 3.14159265
#define ls l,m,rt<<1
#define rs m+1,r,rt<<1|1
#define eps 1e-7
using namespace std;
const int base=23;
const int N=1e6+100;
const int mod=1e9+7;
struct hash
{
    char s[N];
    ull h[N],qp[N];
    ll p[N],len,val[N];
    void init()
    {
        h[0]=val[0]=0;
        qp[0]=p[0]=1;
        len=strlen(s+1);
        for(int i=1;i<=len;i++)
        {
            qp[i]=qp[i-1]*base;
            h[i]=h[i-1]*base+s[i];
        }
    }
    ull get_hash(int l,int r)
    {
        return h[r]-h[l-1]*qp[r-l+1];
    }
}ac;
bool judge(int l)
{
    ull tmp=ac.get_hash(1,l);
    for(int i=l+1;i<=ac.len;i+=l)
    {
        if(tmp!=ac.get_hash(i,i+l-1))return false;
    }
    return true;
}
int main() {

    while(scanf("%s",ac.s+1))
    {
       ac.init();
       if(ac.len==1&&ac.s[1]==‘.‘)break;
      // printf("%s",ac.s+1);
   //?    for(int i=)
       int ans=-1;
       for(int i=1;i<=ac.len;i++)
       {
            if(ac.len%i==0)
            {
                if(judge(i))
                {
                   ans=i;break;
                }

            }
       }
       printf("%d\n",ac.len/ans);
    }
    return 0;
}