剑指 Offer 06. 从尾到头打印链表

描述：输入一个链表的头节点，从尾到头反过来返回每个节点的值（用数组返回）。

tags: recursive

思路

1. 利用栈来存储，出栈即可

class Solution:
    def reversePrint(self, head: ListNode) -> List[int]:
        res = []
        while head:
            res.append(head.val)
            head = head.next
        return res[::-1]

2. 递归

class Solution:
    def reversePrint(self, head: ListNode) -> List[int]:
        def helper(node):
            if not node:
                return
            helper(node.next)
            res.append(node.val)
        res = []
        helper(head)
        return res