C++深入刨析优先级队列priority_queue的使用

template<class T>
class greater
{
public:
	bool operator()(const T& p1, const T& p2) const
	{
		return p1 > p2;
	}
};
struct person
{
	person(string name = "", int age = -1)
		:_name(name)
		, _age(age)
	{}
	bool operator<(const person& p) const
	{
		return _age < p._age;
	}
	bool operator>(const person& p) const
	{
		return _age > p._age;
	}
	string _name;
	int _age;
};
ostream& operator<<(ostream& out, const person& p)
{
	out << "name:" << p._name << "   " << "age:" << p._age << endl;
	return out;
}
void test02()
{
	person arr[] = { { "pxl", 23 },
					 { "dyx", 21 }, 
					 { "wjz", 24 }, 
					 { "ztd", 20 } };
	priority_queue<person, vector<person>, greater<person>> pq(arr, arr + sizeof(arr) / sizeof(arr[0]));//小堆
	pq.push(person("yzc", 22));
	cout <<"堆顶元素是："<< pq.top() << endl;
	while (!pq.empty())
	{
		cout << pq.top() << endl;
		pq.pop();
	}
}
int main()
{
	test02();//自定义类型
	system("pause");
	return 0;
}

	template<class T>
	struct less
	{
		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;
		}
	};
	// 优先级队列 -- 大堆 < 小堆 >
	template<class T, class Container = vector<T>, class Compare = less<T>>
	class priority_queue
	{
	public:
		void AdjustUp(int child)
		{
			Compare comFunc;
			int parent = (child - 1) / 2;
			while (child > 0)
			{
				//if (_con[parent] < _con[child])
				if (comFunc(_con[parent], _con[child]))
				{
					swap(_con[parent], _con[child]);
					child = parent;
					parent = (child - 1) / 2;
				}
				else
				{
					break;
				}
			}
		}
		void push(const T& x)
		{
			_con.push_back(x);
			AdjustUp(_con.size() - 1);
		}
		void AdjustDown(int parent)
		{
			Compare comFunc;
			size_t child = parent * 2 + 1;
			while (child < _con.size())
			{
				//if (child+1 < _con.size() && _con[child] < _con[child+1])
				if (child + 1 < _con.size() && comFunc(_con[child], _con[child + 1]))
				{
					++child;
				}
				//if (_con[parent] < _con[child])
				if (comFunc(_con[parent], _con[child]))
				{
					swap(_con[parent], _con[child]);
					parent = child;
					child = parent * 2 + 1;
				}
				else
				{
					break;
				}
			}
		}
		void pop()
		{
			assert(!_con.empty());
			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;
	};