Method nthToLastR3

java/Chapter 2/Question2_2/Question.java:44–50

(LinkedListNode head, int k)

	}	
	
	public static LinkedListNode nthToLastR3(LinkedListNode head, int k) {
		Result res = nthToLastR3Helper(head, k);
		if (res != null) {
			return res.node;
		}
		return null;
	}		
	
	public static LinkedListNode nthToLast(LinkedListNode head, int n) {
		LinkedListNode p1 = head;