priority_queue 模拟与用法

priority_queue 用法

priority_queue

priority_queue 模拟

#include 
namespace sjy
{
	//仿函数 1
	template <typename T>
	class Less
	{
	public:
		bool operator()(const T& x, const T& y)
		{
			return x < y;
		}
	};
	//仿函数 2
	template <typename T>
	class Greater
	{
	public:
		bool operator()(const T& x, const T& y)
		{
			return x > y;
		}
	};

	//优先级队列
	template <typename T, typename Container = vector<T>, typename Compare = Less<T>>
	class priority_queue
	{
	public:
		//堆相关
		void AdjustUp(int child)
		{
			Compare com;
			int parent = (child - 1) / 2;
			while (child > 0)
			{
				if (com(_con[parent], _con[child]))
				{
					swap(_con[parent], _con[child]);
					child = parent;
					parent = (child - 1) / 2;
				}
				else
				{
					break;
				}
			}
		}
		void AdjustDown(int parent)
		{
			Compare com;
			int child = 2 * parent + 1;
			while (child < _con.size())
			{
				if (child + 1 < _con.size() && com(_con[child], _con[child + 1]))
				{
					child++;
				}
				if (com(_con[parent], _con[child]))
				{
					swap(_con[parent], _con[child]);
					parent = child;
					child = 2 * parent + 1;
				}
				else
				{
					break;
				}
			}
		}
		//成员函数
		priority_queue()
		{}
		template <typename InputIterator>
		priority_queue(InputIterator first, InputIterator last)
		{
			while (first != last)
			{
				_con.push_back(*first);
				++first;
			}
			for (int i = (_con.size() - 1 - 1) / 2; i >= 0; i--)
			{
				AdjustDown(i);
			}
		}
		void push(const T& x)
		{
			_con.push_back(x);
			AdjustUp(_con.size() - 1);
		}
		void pop()
		{
			swap(_con[0], _con[_con.size() - 1]);
			_con.pop_back();
			AdjustDown(0);
		}
		const T& top()
		{
			return _con[0];
		}
		size_t size()
		{
			return _con.size();
		}
		bool empty()
		{
			return _con.empty();
		}
	private:
		Container _con;
	};
}