2.2

lastKth.java

/**
 * Created by Readman on 6/23/14.
 */
public class lastKth {
    /*
    time n
    space 1
    * */
    public static ListNode kth(int k, ListNode head) {
        ListNode slow = head;
        ListNode fast = head;
        while (k > 0) {
            fast = fast.next;
            k--;
        }
        while (fast != null) {
            fast = fast.next;
            slow = slow.next;
        }
        return slow;
    }

    public static void main(String[] args) {
        ListNode first = new ListNode(1);
        first.next = new ListNode(2);
        first.next.next = new ListNode(3);
        first.next.next.next = new ListNode(4);
        first.next.next.next.next = new ListNode(5);
        first.next.next.next.next.next = new ListNode(6);
        System.out.println(kth(2,first).val);
    }
}