C++ 容器适配器仿函数与priority_queue的使用

#include <iostream>
#include <algorithm>
#include <vector>
 
class Compare {
public:
    bool operator()(int a, int b) {
        return a < b;
    }
};
 
int main() {
    std::vector<int> numbers = {10, 65, 30, 99, 23};
 
    // 使用仿函数进行排序
    std::sort(numbers.begin(), numbers.end(), Compare());
 
    std::cout << "Sorted numbers: ";
    for (int num : numbers) {
        std::cout << num << " ";
    }
    std::cout << std::endl;
 
    return 0;
}

template<class T>
	struct less
	{
		bool operator()(const T& left, const T& right)
		{
			return left < right;
		}
	};

	template<class T>
	struct greater
	{
		bool operator()(const T& left, const T& right)
		{
			return left > right;
		}
	};

void AdjustUP(int child)
		{
			int parent = ((child - 1) >> 1);
			while (child)
			{
				if (Compare()(c[parent], c[child]))
				{
					swap(c[child], c[parent]);
					child = parent;
					parent = ((child - 1) >> 1);
				}
				else
				{
					return;
				}
			}
		}

		// 向下调整
		void AdjustDown(int parent)
		{
			size_t child = parent * 2 + 1;
			while (child < c.size())
			{
				// 找以parent为根的较大的孩子
				if (child + 1 < c.size() && Compare()(c[child], c[child + 1]))
					child += 1;

				// 检测双亲是否满足情况
				if (Compare()(c[parent], c[child]))
				{
					swap(c[child], c[parent]);
					parent = child;
					child = parent * 2 + 1;
				}
				else
					return;
			}
		}

template<class T, class Container = std::vector<T>, class Compare = less<T>>
	class priority_queue
	{
	public:
		// 创造空的优先级队列
		priority_queue() : c() {}

		template<class Iterator>
		priority_queue(Iterator first, Iterator last)
			: c(first, last)
		{
			// 将c中的元素调整成堆的结构
			int count = c.size();
			int root = ((count - 2) >> 1);
			for (; root >= 0; root--)
				AdjustDown(root);
		}

		void push(const T& data)
		{
			c.push_back(data);
			AdjustUP(c.size() - 1);
		}

		void pop()
		{
			if (empty())
				return;

			swap(c.front(), c.back());
			c.pop_back();
			AdjustDown(0);
		}

		size_t size()const
		{
			return c.size();
		}

		bool empty()const
		{
			return c.empty();
		}

		// 堆顶元素不允许修改，因为：堆顶元素修改可以会破坏堆的特性
		const T& top()const
		{
			return c.front();
		}
        private:
		Container c;
	};