牛客-剑指0ffer-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。

思路：双指针

# -*- coding:utf-8 -*-
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def FindKthToTail(self, head, k):
        # write code here
        temp = head
        a = head
        while(temp != None and k>0):
            temp = temp.next
            k -= 1
        if k > 0:
            return None
        while(temp != None):
            temp = temp.next
            a = a.next
        return a