GESP 2023年12月 C++五级 单选题 第7题

vector<int> operator+(vector<int> lA, vector<int> lB){
    vector<int> lst;
    for (int i = 0; i < lA.size(); i++) lst.push_back(lA[i]);
    for (int i = 0; i < lB.size(); i++) lst.push_back(lB[i]);
    return lst;
}
vector<int> qSort(vector<int> lst){
    if (lst.size() < 2) return lst;
    int pivot = lst[0];
    vector<int> less, greater;
    for (int i = 1; i < lst.size(); i++)
        if (lst[i] <= pivot) less.push_back(lst[i]);
        else greater.push_back(lst[i]);
    return ____________________;   // 在此处填入数据
}

• A. qSort(less) + qSort(greater) + (vector<int>)pivot
• B. (vector<int>)pivot + (qSort(less) + qSort(greater))
• C. (qSort(less) + (vector<int>)pivot + qSort(greater))
• D. qSort(less) + pivot + qSort(greater)

正确答案：C