priority_queue<>指针比较？ [英] priority_queue<> comparison for pointers?

问题描述

所以我使用带有指针的STL priority_queue<> ...我不想使用值类型，因为创建一大堆新对象只是用于优先级队列将是非常浪费。所以...我想这样做：

So I'm using the STL priority_queue<> with pointers... I don't want to use value types because it will be incredibly wasteful to create a bunch of new objects just for use in the priority queue. So... I'm trying to do this:

class Int {
public:
    Int(int val) : m_val(val) {}
    int getVal() { return m_val; }
private:
    int m_val;
}


priority_queue<Int*> myQ;

myQ.push(new Int(5));
myQ.push(new Int(6));
myQ.push(new Int(3));

现在我如何编写一个比较函数，以便在Q中正确排序？或者，有人可以建议替代策略吗？我真的需要priority_queue接口，并希望不使用复制构造函数（因为大量的数据）。感谢

Now how can I write a comparison function to get those to be ordered correctly in the Q? Or, can someone suggest an alternate strategy? I really need the priority_queue interface and would like to not use copy constructors (because of massive amounts of data). Thanks

EDIT： Int只是一个占位符/示例...我知道我可以使用 int 在C / C ++ lol ...

Int is just a placeholder/example... I know I can just use int in C/C++ lol...

推荐答案

一个选择肯定会工作是替换 with shared_ptr< Int> ，然后实现 operator< code> shared_ptr< Int>

One option that will surely work is to replace Int* with shared_ptr<Int> and then implement operator< for shared_ptr<Int>

bool operator<(const shared_ptr<Int> a, const shared_ptr<Int> b)
{
    return a->getVal() < b->getVal();
}

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