剑指Offer 22 链表中倒数第k个节点

链表中倒数第k个节点

输入一个链表，输出该链表中倒数第k个结点。

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

class Solution:
    def FindKthToTail(self, head, k):
        fast = ListNode(0)
        slow = ListNode(0)
        if head == None:
            return None
        safehead = ListNode(head.val)
        safehead.next = head.next
        fast = head
        count = 0
        while count != k:
            if fast == None:
                return None
            fast = fast.next
            count += 1
        slow = safehead
        while fast != None:
            fast = fast.next
            slow = slow.next
        return slow