3 从尾到头打印链表

题目描述

1 import java.util.ArrayList;
2 import java.util.Stack;
3 public class Solution {
4     public ArrayList<Integer> printListFromTailToHead(ListNode listNode) {
5         Stack<Integer> s=new Stack<Integer>();
6         for(ListNode l = listNode;l!=null;l=l.next)
7             s.push(l.val);
8         ArrayList<Integer> newlist = new ArrayList<Integer>();
9         while(!s.isEmpty()){
10             newlist.add(s.pop());
11         }
12         return newlist;
13     }

import java.util.ArrayList;
import java.util.Stack;
public class Solution {
public ArrayList<Integer> printListFromTailToHead(ListNode head) {
Stack<Integer>  s = new Stack<Integer>();
for(;head!=null;head = head.next)
s.push(head.val);
ArrayList<Integer> list = new ArrayList<Integer>();
for( int item : s)
list.add(item);
return list;
}
}

迭代返回的是无序的！！！！！！！！

1 # -*- coding:utf-8 -*-
2 # class ListNode:
3 #     def __init__(self, x):
4 #         self.val = x
5 #         self.next = None
6
7 class Solution:
8     # 返回从尾部到头部的列表值序列，例如[1,2,3]
9     def printListFromTailToHead(self, root):
10         # write code here
11         res = []
12         while root!=None:
13             res.append(root.val)
14             root = root.next
15         return res[::-1]