import java.util.ArrayList;

public class LinkedQueue<E> {

private class Node<E> {

E data;

Node<E> next;

Node(E data, Node<E> next) {

this.data = data;

this.next = next;

}

}

private Node<E> head;

private Node<E> last;

public void enqueue(E item) {

Node<E> newNode = new Node<E>(item, null);

if (null == head) head = newNode;

if (null != last) last.next = newNode;

last = newNode;

}

public E dequeue() {

E answer = head.data;

head = head.next;

return answer;

}

public boolean isEmpty() {

return (head == null);

}

public static void main(String[] args) {

LinkedQueue<Integer> ints = new LinkedQueue<>();

ints.enqueue(1);

ints.enqueue(2);

ints.enqueue(3);

System.out.println(ints.dequeue());

System.out.println(ints.dequeue());

System.out.println(ints.dequeue());

}

}