面试题52：缺少i的乘积数组

vector<int> multiply(const vector<int>& A) {
    int len = A.size();
    vector<int> result(len, );
    result[] = ;
    for (int i = ; i < len; i++)
    {
        result[i] = result[i - ] * A[i - ];    //result[i]保存下三角
    }
    int tmp = ;
    for (int i = len - ; i >= ; i--)
    {
        tmp = tmp * A[i + ];    //tmp保存上三角
        result[i] *= tmp;
    }
    return result;
}