题目:从上到下按层打印二叉树,同一层结点从左至右输出。每一层输出一行。
牛客网:链接
利用列表存储二叉树每一层的节点,在读取列表中当前层节点的同时,存储下一层的节点以备用,以此类推。
中级版:当前页
# -*- coding:utf-8 -*-
# class TreeNode:
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Solution:
# 返回二维列表[[1,2],[4,5]]
def Print(self, pRoot):
# write code here
if not pRoot:
return []
curstack = [pRoot]
result = []
while curstack:
res = []
nextstack = []
for i in curstack:
res.append(i.val)
if i.left:
nextstack.append(i.left)
if i.right:
nextstack.append(i.right)
curstack = nextstack
result.append(res)
return result