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 fast = pHead;
        ListNode slow = pHead;

        if(pHead == null){
            return null;
        }

        for(int i = 0; i < k ; i++){
            if(fast != null){
                fast = fast.next;
            }
            else{
                return null;
            }
        }

        while(fast != null){
            fast = fast.next;
            slow = slow.next;
        }

        return slow;
    }
}