10. The penultimate node in the linked list

• Given a linked list : 1->2->3->4->5, and k = 2
  Back to the list 4->5

 public ListNode getKthFromEnd(ListNode head, int k) {
        ListNode cur = head, pre = head;
        for(int i = 1; i <= k; i++){
            cur = cur.next;
        }

        while(cur != null){
            pre = pre.next;
            cur = cur.next;
        }
        return pre;
    }

• With two pointers , It's really fast