牛客网--链表中倒数第k个结点

题目描述

输入一个链表，输出该链表中倒数第k个结点。

代码

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

    ListNode(int val) {
        this.val = val;
    }
}*/
public class Solution {
    public ListNode FindKthToTail(ListNode head,int k) {
        ListNode pre = head;
        ListNode p = head;
        int count = 0;
        int diff = 0;
        while(p != null)
        {
            p = p.next;
            count++;
            if(diff >= k)
            {
                pre = pre.next;
            }
            diff++;
        }
        if(count < k)
        {
            return null;
        }
        else
        {
            return pre;
        }
    }
}