题解 | #链表中倒数最后k个结点#

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 *   public ListNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param pHead ListNode类 
     * @param k int整型 
     * @return ListNode类
     */
    public ListNode FindKthToTail (ListNode pHead, int k) {
        // write code here
       pHead = inverseListNode(pHead);
       ListNode cur = pHead;
       ListNode resultListNode = null;
       for(int i = 0;i<k;i++){
            if(cur == null){
                return cur;
            }
            ListNode tmp = cur.next;
            cur.next = resultListNode;
            resultListNode = cur;
            cur = tmp;
       }
       return resultListNode;
    }

    public ListNode inverseListNode(ListNode head){
        ListNode resultListNode = null;
        while(head!=null){
        ListNode tmpListNode = head.next;
        head.next = resultListNode;
        resultListNode = head;
        head = tmpListNode;
        }
        return resultListNode;
    }
}