public class p5b {
    static class LinkedListQueue<T> {
        private class Node<T> {
            private T data;
            private Node<T> next;

            Node(T data) {
                this.data = data;
            }
        }

        private Node<T> front, rear;

        void enqueue(T item) {
            Node<T> newNode = new Node<>(item);
            if (tail == null)
                front = rear = newNode;
            else {
                rear.next = newNode;
                rear = newNode;
            }
        }

        T dequeue() {
            if (front == null)
                System.out.println("Queue is empty");
            T data = front.data;
            front = front.next;
            if (front == null)
                rear = null;
            return data;
        }
    }

    static class ArrayQueue<T> {
        private T[] array;
        private int front, rear, capacity;

        @SuppressWarnings("unchecked")
        ArrayQueue(int size) {
            capacity = size;
            array = (T[]) new Object[capacity];
        }

        void enqueue(T item) {
            if ((rear + 1) % capacity == front)
                System.out.println("Queue is full");
            array[rear] = item;
            rear = (rear + 1) % capacity;
        }

        T dequeue() {
            if (front == rear)
                System.out.println("Queue is empty");
            T item = array[front];
            front = (front + 1) % capacity;
            return item;
        }
    }

    public static void main(String[] args) {
        ArrayQueue<Integer> intQueue = new ArrayQueue<>(5);
        intQueue.enqueue(10);
        intQueue.enqueue(20);
        System.out.println(intQueue.dequeue());
        System.out.println(intQueue.dequeue());
        LinkedListQueue<String> stringQueue = new LinkedListQueue<>();
        stringQueue.enqueue("Hello");
        stringQueue.enqueue("World");
        System.out.println(stringQueue.dequeue());
    }
}