过度调用 C++ 优先级队列中自定义比较器类的复制构造函数

问：

我已经声明了一个带有自定义比较器的向量属性。以下是它的完整代码：priority_queue

法典

#include <bits/stdc++.h>

using namespace std;

class Compare
{
private:
    vector<int> vec;

public:
    Compare(const vector<int> &vec) { this->vec = vec; }

    Compare(const Compare &obj)
    {
        this->vec = obj.vec;
        cout << "Copy Constructor Called!\n";
    }

    bool operator()(const int &left, const int &right)
    {
        return vec[left] > vec[right];
    }
};

int main(void)
{
    vector<int> vec = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    priority_queue<int, vector<int>, Compare> pq{Compare(vec)};

    cout << "Pushing 1\n";
    pq.push(1);
    cout << "Pushed 1\n";
    cout << "Pushing 2\n";
    pq.push(2);
    cout << "Pushed 2\n";

    while (!pq.empty())
    {
        cout << "Popped = " << pq.top() << '\n';
        pq.pop();
    }
    return 0;
}

但是输出很奇怪！！

输出

Copy Constructor Called!
Copy Constructor Called!
Copy Constructor Called!
Copy Constructor Called!
Pushing 1
Copy Constructor Called!
Copy Constructor Called!
Copy Constructor Called!
Pushed 1
Pushing 2
Copy Constructor Called!
Copy Constructor Called!
Copy Constructor Called!
Pushed 2
Popped = 1
Copy Constructor Called!
Copy Constructor Called!
Copy Constructor Called!
Copy Constructor Called!
Copy Constructor Called!
Popped = 2
Copy Constructor Called!

为什么复制构造函数在每次推送和弹出操作时都会被调用这么多次？

也没有任何推送或弹出操作，当我刚刚声明 时，复制构造函数被调用了 4 次priority_queue

为什么会这样？priority_queue存储比较器类对象并在需要比较时使用它，这难道不是正确的吗？