剑指14-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。

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辅助指针

从头到尾遍历链表，辅助指针总是指向当前访问节点的之前的第k个节点。

class Solution:
    def FindKthToTail(self, head, k):
        # write code here
        if k < 1 or head is None:
            return None
        node_k = head
        for i in range(1, k):
            head = head.next
            if head is None:
                return None
        while head.next is not None:
            head = head.next
            node_k = node_k.next
        return node_k