输入一个链表，输出该链表中倒数第k个结点。

package com.alipay.sofa.isle.sample;

 class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}
public class Solution {
    public static ListNode FindKthToTail(ListNode head,int k) {
        ListNode res = new ListNode(0);
        find(head ,k ,res);
        return res.val == 0 ? null : res;
    }

    public  static  int find(ListNode head,int k ,ListNode res) {

        if(head == null) {
            return 1;
        } else {
            int count = find(head.next , k ,res);
            if(count == k) {
                res.val = head.val;
            } else if(count < k){
                res.next = head;
                res = head;
            }
            return count + 1;
        }
    }

    public static void main(String[] args) {
        ListNode node1 = new ListNode(1);
        ListNode node2 = new ListNode(2);
        ListNode node3 = new ListNode(3);
        ListNode node4 = new ListNode(4);
        ListNode node5 = new ListNode(5);
        node1.next = node2;
        node2.next = node3;
        node3.next = node4;
        node4.next = node5;
        FindKthToTail(node1 , 5);
    }
}