每天刷一道牛客题霸-第18天-链表中倒数第K个节点

题目

https://www.nowcoder.com/practice/529d3ae5a407492994ad2a246518148a?tpId=190&&tqId=35368&rp=1&ru=/ta/job-code-high-rd&qru=/ta/job-code-high-rd/question-ranking

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

    ListNode(int val) {
        this.val = val;
    }
}*/
public class Solution {
    public ListNode FindKthToTail(ListNode head,int k) {
        if(head==null)
        {
            return null;
        }
        if(k==1&&head.next==null)
        {
            return head;
        }
        int max=1;
        ListNode node=head;
        ListNode nodeHead=head;
        while((node=node.next)!=null)
        {
            max++;
        }
        node=head;
        if(max<k)
        {
            return null;
        }
        for(int i = 1 ;i <=max-k;i++)
        {
            nodeHead=nodeHead.next;
            node=nodeHead;
        }
        return node;
    }
}