KMP算法

#include<iostream>
#include<cstring>
#include<cstdio>
#include<string>
#include<algorithm>
using namespace std;
#define N 100010

char s[N * 10], p[N];
int nextval[N];
int lens, lenp;

void getnext()
{
    int i = 0, j = -1;
    nextval[0] = -1;
    while(i != lenp)
    {
        if(j == -1 || s[i] == s[j])
            {
                nextval[++i] = ++j;
            }
        else
            j = nextval[j];
    }
}

int KMP()
{
    int i = 0, j = 0, count = 0;
    while(i != lens && j != lenp)
    {
        if(s[i] == p[j] || j == -1)
            ++i, ++j;
        else
            j = nextval[j];
        if(j == lenp)
        {
            count++;
            j = nextval[j];
        }
    }
    return count;
}

int main()
{
    int ncase;
    int len;
    int ans;
    scanf("%d", &ncase);
    while(ncase--)
    {
        scanf("%s%s", p, s);
        lens = strlen(s);
        lenp = strlen(p);
        getnext();
        ans = KMP();
        printf("%d\n", ans);
    }
    return 0;
}

 KMP算法问题解决：在一个字符串中定位另一个串