题解 | #按之字形顺序打印二叉树#

# 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 as Q
class Solution:
    def Print(self , pRoot: TreeNode) -> List[List[int]]:
        # write code here
        res = []
        que = Q.Queue()
        if pRoot:
            que.put(pRoot)
        flag = 0
        while not que.empty():
            outrow = []
            length = que.qsize()
            for i in range(length):
                this = que.get()
                outrow.append(this.val)
                if this.left:
                    que.put(this.left)
                if this.right:
                    que.put(this.right)
            if flag == 0:
                res.append(outrow)
                flag = 1
            else:
                outrow.reverse()
                res.append(outrow)
                flag = 0

        return res