//BF 算法int BFmatch(char *s,char *p){    int i,j;    i = 0;    while(i<strlen(s))    {        j = 0;        while(s[i] == p[j] && j<strlen(p))        {            i++;            j++;        }        if(j == strlen(p))        return i - strlen(p);        i = i - j + 1;   // 指针 i回溯    }    return -1;}