priority_queue声明和bool操作符<宣言 [英] priority_queue declaration and bool operator < declaration

问题描述

我的问题是：

• 我有我的程序2类加主>
  

• 我已在类的成员函数中声明了priority_queue;




• 我认为应该使用的代码是：

    //确定优先级（在优先级队列中）
   bool operator< ; （const node& a，const node& b）
   {
   return a.getPriority（）> b.getPriority（）; 
  } 
    

问题：我插入这段代码？

解决方案

这看起来像是你的运算符< 可能是对节点的一个不好的补充。问自己：节点是逻辑上可比的？很明显，比较节点（在priorty_queue的上下文之外）应该比较它们的优先级吗？也许它应该比较自己的位置，或任何他们可能包含的东西。如果你提供一个运算符< ，还有其他5个比较运算符也是有意义的。如果不清楚什么节点<节点实际上进行比较，不为节点提供运算符<。在这种情况下，最好为 priority_queue ...

提供自定义比较器。

  struct NodeComparer 
 {
 bool operator（）（const node& left，const node& right）
 {
 return left.GetPriority（） right.GetPriority（）; 
} 
} 
  

...

  std :: priority_queue< node，std :: vector< node> ;, NodeComparer> nodeQueue; 
  

这样，您的 priority_queue 但您不会向节点添加不合逻辑的功能。

my problem is:

• I have my program with 2 class plus the main;

• I've declared a priority_queue inside a member function of a class;

• I have to define the comparison and I think the code I should use is:

  // Determine priority (in the priority queue)
  bool operator < (const node & a, const node & b)
  {
    return a.getPriority() > b.getPriority();
  }
  

Question: where Should I insert this piece of code? Could someone help me?

thanks

解决方案

It looks like your operator< is possibly a poor addition to node. Ask yourself: are nodes logically comparable? Is it clear that comparing nodes (outside of the context of priorty_queue) should compare their priority? Maybe it should compare their position, or anything else they might contain. If you supply an operator< it will also make sense to have the other 5 comparison operators. If it's not clear what node < node actually compares, don't provide an operator< for nodes. In cases like this it's better to provide a custom comparer to the priority_queue...

struct NodeComparer
{
    bool operator()(const node& left, const node& right)
    {
        return left.GetPriority() > right.GetPriority();
    }
}

...

std::priority_queue<node, std::vector<node>, NodeComparer> nodeQueue;

This way your priority_queue can work as desired but you don't add illogical functionality to node.

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