hdu1686_VJkuangbin16kmp_

题目大意:给定文本串和模式串,问模式串在文本串中出现了多少次(可重叠)

打板子。。。

#include <cstdio>
#include <cstring>

using namespace std;
const int maxn = 1000010;
const int maxm = 10010;
int n, m;
char s[maxn], p[maxm];
int next[maxm];

void getnext()
{
    int i = 0, j = -1;
    next[0] = -1;
    while(i < m)
    {
        if(j==-1 || p[i]==p[j])
        {
            ++i;
            ++j;
            next[i] = j;
        }
        else j = next[j];
    }
}

int kmp()
{
    int i = 0, j = 0, cnt = 0;
    getnext();
    while(i < n)
    {
        if(j==-1 || s[i]==p[j])
        {
            ++i;
            ++j;
        }
        else j = next[j];
        if(j == m)
        {
            ++cnt;
            --i;
            --j;
            j = next[j];
        }
    }
    return cnt;
}

int main()
{
    int t;
    scanf("%d", &t);
    while(t--)
    {
        scanf("%s", p);
        scanf("%s", s);
        m = strlen(p);
        n = strlen(s);
        int ans = kmp();
        printf("%d\n", ans);
    }
    return 0;
}

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转载自blog.csdn.net/jay__bryant/article/details/80726553