priority

namespace sakeww
{

	//普通模式
	template<class T>
	struct Less//Less->仿函数 less就叫函数对象
	{
		bool operator()(const T& x, const T& y) const
		{
			return x < y;
		}
	};
	template<class T>
	struct Greater {
		bool operator()(const T& x, const T& y) const {
			return x > y;
		}
	};

	// 大的优先级高--大堆
	template<class T, class Container = vector<T>, class Compare = Less<T>>
	class priority_queue
	{
	private:
		void adjust_up(size_t child)
		{
			Compare com;
			size_t parent = (child - 1) / 2;
			while (child > 0)
			{
				//if(_con[child] > _con[parent]) 
				//等价于 if(_con[parent] < _con[child])
				if (com(_con[parent], _con[child]))
				{
					swap(_con[child], _con[parent]);
					child = parent;
					parent = (child - 1) / 2;
				}
				else break;
			}
		}

		void adjust_down(size_t parent)
		{
			Compare com;

			size_t child = (parent * 2) + 1;
			while (child < _con.size())
			{
				//if (child + 1 < _con.size() && _con[child + 1] > _con[child])
				if (child + 1 < _con.size() && com(_con[child], _con[child + 1]))
				{
					++child;
				}

				//if (_con[child] > _con[parent])
				if (com(_con[parent], _con[child]))
				{
					swap(_con[child], _con[parent]);
					parent = child;
					child = parent * 2 + 1;
				}
				else break;
			}
		}

	public:
		priority_queue()
		{}

		template <class InputIterator>
		priority_queue(InputIterator first, InputIterator last)
			:_con(first, last)
		{
			// 建堆
			for (int i = (_con.size() - 1 - 1) / 2; i >= 0; --i)
			{
				adjust_down(i);
			}
		}

		void push(const T& x)
		{
			_con.push_back(x);
			adjust_up(_con.size() - 1);
		}

		void pop()
		{
			//assert(!_con.empty());
			swap(_con[0], _con[_con.size() - 1]);
			_con.pop_back();
			adjust_down(0);
		}

		const T& top()
		{
			return _con[0];
		}

		size_t size()
		{
			return _con.size();
		}

		bool empty()
		{
			return _con.empty();
		}
	private:
		Container _con;//随机容器
	};
}