Method removeFirst

12_LinkedList.java/DLL.java:40–54

()

        }

        public int removeFirst() {
            if(head == null) {
                return Integer.MIN_VALUE;
            }
            size--;
            if(head == tail) {
                int val = head.data;
                head = tail = null;
                return val;
            }
            int val = head.data;
            head = head.next;
            head.prev = null;
            return val;
        }
        
    public void reverse() {
        Node curr = head;