Ctrl F 2

#include<stdio.h>
typedef long long int ll;
ll const prime = 98765431;

int main()
{
    int n,m;
    scanf("%d %d",&n,&m);
    char str[n+1];
    scanf("%s",str);
    char word[m+1];
    scanf("%s",word);
    ll mb = 1;
    ll hw = 0;

    for(int i = 0 ; i < m ; i ++){
        if(i != 0)mb *= prime;
        hw *= prime;
        hw += word[i];
    }
    ll hs = 0;
    int cnt = 0;
    for(int i = 0 ; i < n ; i ++){
        hs *= prime;
        hs += str[i];
        if(i >= m - 1){
    //  printf("I %d : Test %lld == %lld ? \n",i,hs,hw);
            if(hs == hw){
                cnt ++;
            }
            hs -= str[i-m+1]*mb;
        }

    }
    printf("%d",cnt);
    return 0;
}