题解 | #链表中倒数第k个结点#

public class Solution {
    public ListNode FindKthToTail(ListNode head,int k) {
        if(k <= 0 || head==null){//避免空指针异常
            return null;
        }
        ListNode fast = head;
        ListNode slow = head;
        while(k-1!=0){//fast先走k-1步
            fast = fast.next;
            if(fast==null){
                return null;//fast为空，说明k的值超出链表长度
            }
            k--;
        }
        while(fast.next!=null){
            fast = fast.next;
            slow = slow.next;
        }
        return slow;
    }
}