【CF1016B】Segment Occurrences（模拟）

题意：给定两个串s和t，多次询问s的一个区间[l ,r]中有多少个子串与t串相同

len<=1e3,q<=1e5

思路：前缀和

 #include<cstdio>
 #include<cstring>
 #include<string>
 #include<cmath>
 #include<iostream>
 #include<algorithm>
 #include<map>
 #include<set>
 #include<queue>
 #include<vector>
 using namespace std;
 typedef long long ll;
 typedef unsigned int uint;
 typedef unsigned long long ull;
 typedef pair<int,int> PII;
 typedef vector<int> VI;
 #define fi first
 #define se second
 #define MP make_pair
 #define MOD 1000000007
 #define N   210000

 char a[N+],b[N+];
 int s[N+];
 ll n,m,q;

 int read()
 {
    int v=,f=;
    char c=getchar();
    while(c<||<c) {if(c=='-') f=-; c=getchar();}
    while(<=c&&c<=) v=(v<<)+v+v+c-,c=getchar();
    return v*f;
 }

 int main()
 {
       //freopen("2.in","r",stdin);
     //freopen("2.out","w",stdout);
     scanf("%d%d%d",&n,&m,&q);
     scanf("%s",a+);
     scanf("%s",b+);
     for(int i=;i<=N-;i++) s[i]=;
     for(int i=m;i<=n;i++)
     {
         int flag=;
         for(int j=;j<=m;j++)
          if(b[m-j+]!=a[i-j+]){flag=;break;}
         s[i]=s[i-]+flag;
     }
     for(int i=;i<=q;i++)
     {
         int x,y;
         scanf("%d%d",&x,&y);
         int t;
         if(y-x+<m) t=;
          else t=s[y]-s[x+m-];
         printf("%d\n",t);
     }
     return ;
 }