算法题-从尾到头打印链表

[编程题]从尾到头打印链表

题目描述:

输入一个链表,从尾到头打印链表每个节点的值

常规问题没什么费劲的,应该很容易想到利用栈的后进先出特性,将整个链表顺序压栈后弹出至动态数组中

C++

/**
*  struct ListNode {
*        int val;
*        struct ListNode *next;
*        ListNode(int x) :
*              val(x), next(NULL) {
*        }
*  };
*/

class Solution {
public:
vector<int> printListFromTailToHead(ListNode* Head) {
        stack<int> tmpstack;
        vector<int> ans;
        while(Head != NULL)
        {
           tmpstack.push(Head->val);
            Head = Head->next;
        }
        while(!tmpstack.empty())
       {
            ans.push_back(tmpstack.top());
            tmpstack.pop();
        }
        return ans;
    }
};

2.python解法：先将链表中的值插入到新序列newlist中，之后再使用list的切片操作将序列逆置，则输出序列即可

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

class Solution:
    # 返回从尾部到头部的列表值序列，例如[1,2,3]
    def printListFromTailToHead(self, listNode):
        newlist =[]
        while listNode is not None:
            newlist.append(listNode.val)
            listNode = listNode.next
        return newlist[::-1]