题目描述
blablabla
样例
blablabla
算法1
() $O(n^2)$
blablabla
时间复杂度分析:blablabla
Python 代码
# Definition for a binary tree node.
# class TreeNode(object):
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
from collections import deque
class Solution:
def printFromTopToBottom(self, root):
"""
:type root: TreeNode
:rtype: List[int]
"""
if not root:
return []
res = []
queue = deque([root])
while queue:
node = queue.popleft()
res.append(node.val)
if node.left:
queue.append(node.left)
if node.right:
queue.append(node.right)
return res