POJ 3461 Oulipo KMP

题意：统计其中一个子串的出现次数

题解：即KMP算法中j==m的次数

//作者:1085422276
#include <cstdio>
#include <cmath>
#include <cstring>
#include <ctime>
#include <iostream>
#include <algorithm>
#include <set>
#include <vector>
#include <sstream>
#include <queue>
#include <typeinfo>
//#include<bits/stdc++.h>
#include <map>
#include <stack>
typedef long long ll;
using namespace std;
const int inf = 10000000;
inline ll read()
{
    ll x=0,f=1;
    char ch=getchar();
    while(ch<'0'||ch>'9')
    {
        if(ch=='-')f=-1;
        ch=getchar();
    }
    while(ch>='0'&&ch<='9')
    {
        x=x*10+ch-'0';
        ch=getchar();
    }
    return x*f;
}
ll exgcd(ll a,ll b,ll &x,ll &y)
{
    ll temp,p;
    if(b==0)
    {
        x=1;
        y=0;
        return a;
    }
    p=exgcd(b,a%b,x,y);
    temp=x;
    x=y;
    y=temp-(a/b)*y;
    return p;
}
//*******************************
int p[1000001];
int main()
{
   int T;
   scanf("%d",&T);
    while(T--)
    {
        string a,b;
        cin>>b>>a;
        a=" "+a;
        b=" "+b;
        int m=b.length();
        int n=a.length();
        n--,m--;
        memset(p,0,sizeof(p));
        int j=0;
        for(int i=2;i<=m;i++)
        {
            while(j>0&&b[j+1]!=b[i])j=p[j];
            if(b[j+1]==b[i])j++;
            p[i]=j;
        }
        int ans=0;
        j=0;
        for(int i=1;i<=n;i++)
        {
            while(j>0&&b[j+1]!=a[i])j=p[j];
            if(b[j+1]==a[i])j++;
             if(j==m){
                ans++;
             }
        }
        cout<<ans<<endl;
    }
    return 0;
}