public class CircularQueue {
	private int[] queue;
	private int front;
	private int rear;
	private int size;
	private int capacity;

	public CircularQueue(int capacity) {
		this.capacity = capacity;
		this.queue = new int[capacity];
		this.front = 0;
		this.rear = 0;
		this.size = 0;
	}

	public boolean isFull() {
		return size == capacity;
	}

	public boolean isEmpty() {
		return size == 0;
	}

	public void enqueue(int data) {
		if (isFull()) {
			throw new RuntimeException("Queue is full");
		}
		queue[rear] = data;
		rear = (rear + 1) % capacity;
		size++;
	}

	public int dequeue() {
		if (isEmpty()) {
			throw new RuntimeException("Queue is empty");
		}
		int data = queue[front];
		front = (front + 1) % capacity;
		size--;
		return data;
	}

	public int peek() {
		if (isEmpty()) {
			throw new RuntimeException("Queue is empty");
		}
		return queue[front];
	}

	public int getSize() {
		return size;
	}

	public void displayCircularQueue() {
		if (isEmpty()) {
			throw new RuntimeException("Queue is empty");
		}
		int i = front;
		int count = 0;
		while (count < size) {
			System.out.print("["+ queue[i] + "]");
			i = (i + 1) % capacity;
			count++;
		}
		System.out.println();
	}

	public int getMiddle() {
		if (isEmpty()) {
			throw new RuntimeException("Queue is empty");
		}
		int middleIndex = (front + size / 2) % capacity;
		return queue[middleIndex];
	}
}

// Main
public class Main {

	public static void main(String[] args) {
		CircularQueue circularQueue = new CircularQueue(5);
		CircularQueue.enqueue(10);
		CircularQueue.enqueue(20);
		CircularQueue.enqueue(30);
		CircularQueue.enqueue(40);
		CircularQueue.enqueue(50);
		CircularQueue.displayCircularQueue();
		System.out.println();

		System.out.println("Middle element: " + circularQueue.getMiddle());
		circularQueue.displayCircularQueue();
		System.out.println();

		System.out.println("===DEQUEU===");
		System.out.println(circularQueue.dequeue());
		circularQueue.enqueue(60);
		circularQueue.displayCircularQueue();
		System.out.println();

		System.out.println("Middle element: " + circularQueue.getMiddle());
		circularQueue.displayCircularQueue();
	}
}

// === 출력 ===
/*
[10][20][30][40][50]

Middle element: 30
[10][20][30][40][50]

===DEQUEU===
10
[20][30][40][50][60]

Middle element: 40
[20][30][40][50][60]
*/