牛客网 从上往下打印二叉树

# -*- coding:utf-8 -*-
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class Solution:
    # 返回从上到下每个节点值列表，例：[1,2,3]
    def PrintFromTopToBottom(self, root):
        # write code here
        if not root:
            return []
        tmp_array=[]
        tmp_array.append(root)
        result_array=[]
        while len(tmp_array)>0:
            cur_node=tmp_array.pop(0)
            result_array.append(cur_node.val)
            if cur_node.left:
                tmp_array.append(cur_node.left)
            if cur_node.right:
                tmp_array.append(cur_node.right)

        return result_array