学步园

计算串x在y中重复了多少次，可重叠。

/************************************************
 * Author: yew1eb
 * Created Time: 2014/3/6 16:30:33
 * File Name: poj3461.cpp
 *************************************************/
#include <algorithm>
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cctype>
#include <cstdio>
#include <string>
#include <vector>
#include <cmath>
#include <stack>
#include <queue>
#include <ctime>
#include <set>
#include <map>
using namespace std;
#define INF 0x3f3f3f3f
#define eps 1e-8
#define pi acos(-1.0)
typedef long long ll;
const int maxn = 10000 + 10;

int f[maxn];

void getFail(char* P, int* f)  
{  
    int i, j;  
    int m = strlen(P);  
    j = f[0] = -1;  
    i = 0;  
    while(i<m)  
    {  
        while(-1!=j && P[i] != P[j] ) j = f[j];  
        f[++i] = ++j;  
    }  
}  

int count(char* x, char* y)
{
    int n = strlen(y);
    int m = strlen(x);
    getFail(x, f);
    int j = 0;
    int ans = 0;
    for(int i=0; i < n; ++i)
    {
        while(j && y[i] != x[j]) j = f[j];
        if(y[i] == x[j] ) j++;
        if(j >= m) 
        {
            ans++;
            j = f[j];
        }
    }
    return ans;
}

int main()
{
    int n;
    char x[maxn], y[1000000 + 10];
    while(~scanf("%d",&n) )
    {
        scanf("%s",x);
        scanf("%s",y);
        int ans = count(x, y);
        printf("%d\n",ans);
    }
    return 0;
}