题解 | #按之字形顺序打印二叉树#

from math import inf
#from math import inf
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param pRoot TreeNode类 
# @return int整型二维数组
#
import queue
class Solution:
    def Print(self , pRoot: TreeNode) -> List[List[int]]:
        res = []
        if not pRoot:
            return []
        info = queue.Queue()
        info.put(pRoot)
        leftToRight = True
        while not info.empty():
            row = []
            n =  info.qsize()
            for i in range(n):
                tmp = info.get()
                row.append(tmp.val)
                if tmp.left:
                    info.put(tmp.left)
                if tmp.right:
                    info.put(tmp.right)
            if leftToRight:
                res.append(row)
                leftToRight = False
            else:
                res.append(row[::-1])
                leftToRight = True
        return res