kmp失效函数(测试博客的编辑器)

int *find_next(char *p)
{
    int k = -1;                            //right shift i-k 
    int i = 0;
    int m = strlen(p);
    int *next = (int *)malloc(sizeof (int) * m);        
    next[0] = -1;
                                        //maintain the k is the length of longest matching prefix of p[i]
    while (i < m-1) {                    //after i++, i == m-1, the last index of element in next[]
        while (k >= 0 && p[i] != p[k])    //how to assure the k is the length of longest matching substring of p[i]??
            k = next[k];
        i++;
        k++;
        next[i] = k;
    }
    return next;
}