1344: PIPI的字符串问题Ⅱ

这道题使用了字符串哈希，模数为ull自然溢出

#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ull;
const int N=1e6+10, base=23333;
ull hs1[N],hs2,pw=1;
char s[N],t[N];
int main(){scanf("%s%s",s+1,t+1);int n= strlen(s+1),m=strlen(t+1);for(int i=1;i<=n;i++){hs1[i]=hs1[i-1]*base+s[i];}for(int i=1;i<=m;i++){hs2=hs2*base+t[i];pw*=base;}int ans=0;for(int i=m;i<=n;i++){if(hs1[i]-hs1[i-m]*pw==hs2)ans++;}if(ans){printf("YES\n%d",ans);}else{printf("NO");}return 0;
}