Method enqueue

src/main/java/edu/princeton/cs/algs4/Queue.java:96–104

Adds the item to this queue. @param item the item to add

(Item item)

     * @param  item the item to add
     */
    public void enqueue(Item item) {
        Node<Item> oldlast = last;
        last = new Node<Item>();
        last.item = item;
        last.next = null;
        if (isEmpty()) first = last;
        else           oldlast.next = last;
        n++;
    }

    /**
     * Removes and returns the item on this queue that was least recently added.