public class Queue
{
	private int count;//element number of queue
	private int head;//index of header
	private int tail;//index  of tail
	private int MAXSIZE = 10;//capacity
	private int space [];

	//Constructor
	public Queue()
	{
		count = 0;
		head = tail = -1;
		space = new int[MAXSIZE];
	}

	//Inspector
	public boolean isEmpty()
	{
		return (count == 0);
	}

	public int front()
	{
		if(count == 0) return -1;
		return space[head];
	}

	public int rear()
	{
		if(count == 0) return -1;
		return space[tail];
	}

	public String toString()
	{
		String str = "[";
		int j = head;
		for(int i = 0; i < count; i++)
		{
			str = str+" "+space[j];
			j = (j+1)%MAXSIZE;
		}

		return str + "]";
	}

	//Modifier
	public void enqueue(int e)
	{
		if(count == MAXSIZE)
		{
			int [] space2 = new int[MAXSIZE*2];
			int j = head;
			int k = 0;
			for(int i = 0; i < MAXSIZE; i++)
			{
				space2[k] = space[j];
				j = (j+1)%MAXSIZE;
				k++;
			}
			space = space2;
			head = 0;
			tail = MAXSIZE-1;
			space[tail+1] = e;
			MAXSIZE = MAXSIZE*2;
			count++;
			tail++;
		}
		else{
			space[(tail+1)%MAXSIZE] = e;
			count++;
			tail = (tail+1)%MAXSIZE;
			if(count == 1)
				head = tail;
		}
	}

	public boolean dequeue()
	{
		if(count == 0) return false;
		if(count == 1)
		{
			head = tail = -1;
			count = 0;
			return true;
		}
		head = (head+1)%MAXSIZE;
		count--;
		return true;
	}
}
			

public class QueueTest
{
	public static void main(String args[])
	{
		Queue q = new Queue();

		for(int i = 0; i < 11; i++)
			q.enqueue(i);

		System.out.println(q);

		q.dequeue();
		q.enqueue(11);

		System.out.println(q);
	}
}