Python：把二叉树打印成多行

题目描述

# -*- 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 []
res, tree = [], [pRoot]
while tree:
row, sub_tree = [], []
for item in tree:
row.append(item.val)
if item.left:
sub_tree.append(item.left)
if item.right:
sub_tree.append(item.right)
res.append(row)
tree = sub_tree
return res