KMP

    for (int i = 2, j = 0; i <= m; i ++ )
    {
        while (j && p[i] != p[j]) j = ne[j];
        if (p[i] == p[j]) j ++ ;
        ne[i] = j;
    }

    for (int i = 0, j = 0; i <= n; i ++ ) {
        while (j && s[i] != p[j]) j = ne[j];
        if (s[i] == p[j]) j++;
        if (j == m){
            // 匹配成功后的逻辑
            cout << i - m + 1 << endl;
            break;
        }
    }