Problem2-2.java

public Node findLastKth(Node head, int k) {
  // Assume k > 0
  if (k <= 0 || head == null)
    return null;
    
  Node current = head;
  Node runner = current;
  while (k > 0 && runner != null) {
    k--;
    runner = runner.next;
  }
  
  if (runner == null) {
    // There aren't enough items in the list
    return null;
  }
  
  // current is at head
  // runner is k step up
  while (runner != null) {
    runner = runner.next;
    current = current.next;
  }
  
  return current;
}