如何在优先队列中找到价值? [英] How I can find value in priority queue?

问题描述

我想在我的优先队列中找到一个节点，但我没有找到解决方案 :(如果你有解决方案，我很感兴趣.

I would like to find a node in my priority queue but I did not find a solution :( If you have a solution, I'm interested.

谢谢帮助.

推荐答案

如果你真的需要搜索一个 std::priority_queue 并且想要高效地完成它，你可以派生一个新类并添加find 成员函数.由于您没有添加任何其他状态，因此您不必担心切片或其他问题，因为 std::priority_queue 不是多态的.

If you really need to search through a std::priority_queue and want to do it efficiently you can derive a new class and add a find member function. Since you are not adding any additional state you do not have to worry about slicing or other issues since std::priority_queue is not polymorphic.

#include <queue>
template<
    class T,
    class Container = std::vector<T>,
    class Compare = std::less<typename Container::value_type>
> class MyQueue : public std::priority_queue<T, Container, Compare>
{
public:
    typedef typename
        std::priority_queue<
        T,
        Container,
        Compare>::container_type::const_iterator const_iterator;

    const_iterator find(const T&val) const
    {
        auto first = this->c.cbegin();
        auto last = this->c.cend();
        while (first!=last) {
            if (*first==val) return first;
            ++first;
        }
        return last;
    }
};

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