c++ - C++ 中 std::priority_queue 的比较器部分是什么意思？

Question

C++ 中的优先级队列语法:

priority_queue <Type, vector<Type>, ComparisonType > min_heap;

如果我想声明一个最大堆，我使用std::less，否则使用std::greater(最小堆)。我不太明白为什么 std::less 导致最大堆，而 std::greater 最小堆？

Answer 1

引自 cppreference解释了这个概念:

Compare - A Compare type providing a strict weak ordering.

Note that the Compare parameter is defined such that it returns true if its first argument comes before its second argument in a weak ordering. But because the priority queue outputs largest elements first, the elements that "come before" are actually output last. That is, the front of the queue contains the "last" element according to the weak ordering imposed by Compare.