中国(北方)大学生程序设计训练赛(第二周)(Problem A: Common Substrings-hash)

给你2个字符串，问第一个字符串有几个后缀是另一个的前缀。

hash

#include <iostream>
#include <cmath>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <string>
#include <vector>
#include <map>
#include <functional>
#include <cstdlib>
#include <queue>
#include <stack>
using namespace std;
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
typedef long long ll;
typedef unsigned long long ull;
ll mul(ll a,ll b){return (a*b)%F;}
ll add(ll a,ll b){return (a+b)%F;}
ll sub(ll a,ll b){return (a-b+llabs(a-b)/F*F+F)%F;}
void upd(ll &a,ll b){a=(a%F+b%F)%F;}
int read()
{
    int x=0,f=1; char ch=getchar();
    while(!isdigit(ch)) {if (ch=='-') f=-1; ch=getchar();}
    while(isdigit(ch)) { x=x*10+ch-'0'; ch=getchar();}
    return x*f;
} 
#define
ull h[MAXN],p[MAXN];
char s[MAXN],s2[MAXN];
int main() {
    // freopen("A.in","r",stdin);
    int T=read();
    while(T--) {
        scanf("%s%s",s+1,s2+1);
        int n=strlen(s+1),m=strlen(s2+1);
        h[0]=0;
        p[1]=1;
        Fork(i,2,n) p[i]=p[i-1]*10007;
        For(i,m) h[i]=h[i-1]*10007+s2[i];
        ull t=0;
        int j=0,ans=0;
        ForD(i,n) {
            t+=s[i]*p[n-i+1];
            if (h[++j]==t) ans++;
            if (j==m)break;
        }
        printf("%d\n",ans);
    }

    return 0;
}