KMP算法模板

http://www.matrix67.com/blog/archives/115

求next函数模板：

void GetNext(char *s)
{
    int len = strlen(s);
    int i,j;
    i = 0; j = -1;//j从0开始，i从1开始
    next[0] = -1;
    for (i = 1; i < len; ++i)
    {
        while (j > -1 && s[j + 1] != s[i])//不相同的话j就跳跃知道相同或者成为-1
        j = next[j];
        if (s[j + 1] == s[i]) ++j;//相同更新j
        next[i] = j;//每一次都要求出next[i]
    }
}

　　

kmp模板：

void kmp(char *s1,char *s2)//s1副串 s2主串
{
    int len1 = strlen(s1);
    int len2 = strlen(s2);
    int i,j = -1;
    int ans = 0;
    for (i = 0; i < len2; ++i)
    {
        while (j > -1 && s1[j + 1] != s2[i]) j = next[j];
        if (s1[j + 1] == s2[i]) ++j;
        if (j == len1 - 1)//找到子串，后继续查找
        {
            ans++;
            j = next[j];
        }
    }
    printf("%d\n",ans);
}