题解 | #链表中倒数最后k个结点#

using System;
using System.Collections.Generic;

/*
public class ListNode
{
    public int val;
    public ListNode next;

    public ListNode (int x)
    {
        val = x;
    }
}
*/

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
        ListNode listNode = new ListNode(0);
        int nLnLen = 0;
        while (pHead != null) {
            ListNode lnTmp = pHead.next;
            pHead.next = listNode.next;
            listNode.next = pHead;
            pHead = lnTmp;
            nLnLen++;
        }
        ListNode listNodeTmp = listNode.next;
        listNode.next = null;//中断复用
        int nIndex = 0;
        for (; nIndex < k && listNodeTmp != null; nIndex++) {
            ListNode lnTmp = listNodeTmp.next;
            listNodeTmp.next = listNode.next;
            listNode.next = listNodeTmp;
            listNodeTmp = lnTmp;
        }
        return k > nLnLen ? null : listNode.next;
    }
}