剑指offer--链表中倒数第k个结点

剑指offer–链表中倒数第k个结点

一、前言

最近开始刷剑指offer，记录一下。牛客网在线编程板块的剑指offer专区。
牛客网剑指offer：传送门
或者点击下方链接。
https://www.nowcoder.com/ta/coding-interviews

二、题目描述

输入一个链表，输出该链表中倒数第k个结点。

三、代码

# -*- 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
        # 快慢指针
        firstPoint=head
        secondPoint=head
        for i in range(k):
            if firstPoint == None:
                return None
            firstPoint = firstPoint.next
        while firstPoint !=None:
            firstPoint=firstPoint.next
            secondPoint=secondPoint.next
        return secondPoint
def printChain(node):
    while node:
        print(node.val)
        node=node.next
if __name__ == '__main__':
    s=Solution()
    l1 = ListNode(1)
    l2 = ListNode(2)
    l3 = ListNode(3)
    l4 = ListNode(4)
    l5 = ListNode(5)
    l1.next = l2
    l2.next = l3
    l3.next = l4
    l4.next = l5
    l5.next = None
    print(printChain(l1))
    print(s.FindKthToTail(l1,3))