#include <iostream>
#include <assert.h>
using namespace std;
//Stack  implementation

template<class T>
class Stack
{
public:
	Stack()
		:a(NULL)
		,_top(0)
		,capacity(0)
	{}
	
	~Stack()
	{
		if(a!=NULL)
		{
			delete[] a;
		}
	}

	Stack(const Stack<T>& s)
		:a(s.a)
		,capacity(s._top)
		,_top(s._top)
	{
		s.a=NULL;
	}
	
	Stack<T>& operator=(const Stack<T>& s)
	{
		if(this!=&s)
		{
			swap(a,s.a);
			capacity=s.capacity;
			_top=s._top;
		}
		return *this;
	}
	
	void Push(const T& d)
	{
		_CheckCapacity();
		a[_top++] = d;
	}

	void Pop()  
	{
		if(_top!=0)
		{
			_top--;
		}
	}

	T& top()
	{
		return a[_top-1];
	}

	bool Empty()
	{
		if(_top==0)
			return true;
	}

	size_t Size()
	{
		return _top;
	}

	
protected:
	void _CheckCapacity()  
	{
		int i;
		if(_top==capacity)
		{
			capacity=2*capacity+3;
			T* tmp=new T[capacity];
			for(i=0;i<(_top);i++)
			{
				tmp[i]=a[i];
			}
			delete[] a;
			a=tmp;
		}
	}
private:
	T* a;
	size_t _top;
	size_t capacity;
};

//Queue  implementation
template<class T>
struct Node
{
	Node(const T&d)
		:_data(d)
		,next(NULL)
	{
	}
	T _data;
	Node<T> *next;
};

template<class T>
class Queue
{
public:
	Queue()
		:_head(NULL)
		,_tail(NULL)
		,m(0)
	{ }
	
	~Queue()
	{
		if(_head!=NULL)
		{
			Node<T> *cur=_head;
			Node<T> *del=NULL;
			while(cur)
			{
				del=cur;
				cur=cur->next;
				delete del;
				del=NULL;
				
			}
		}
	}
	void Push(const T& x)
	{
		Node<T>* NewNode=new Node<T>(x);
		if(_head==NULL)
		{
			_head=_tail=NewNode;
			
		}
		else
		{
			NewNode->next=_head;
			_head=NewNode;
		}
		m++;
	}

	void Pop()
	{
		Node<T> *del=NULL;
		if(_head==NULL)
		{
			return;
		}
		else if(_head==_tail)
		{
			delete _head;
			_head=NULL;
		}
		else
		{
			del=_head;
			_head=_head->next;
			delete del;
			del=NULL;
		}
		m--;
	}

	T& Front()
	{
		assert(_head);
		return _head->_data;
	}

	T& Back()
	{
		assert(_head);
		return _tail->_data;
	}

	bool Empty()
	{
		if(_head==NULL)
			return true;
	}

	size_t Size()
	{
		assert(_head);
		return m;
	}

protected:
	Node<T>* _head;
	Node<T>* _tail;
	size_t m;
};