题解 | #按之字形顺序打印二叉树#

#     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
#
class Solution:
    def Print(self , pRoot: TreeNode) -> List[List[int]]:
        if pRoot==None:return None
        res,ceng_stack=[],[pRoot]
        a=1
        while ceng_stack:
            ceng_nodes=[]
            for i in range(len(ceng_stack)):
                    node=ceng_stack.pop(0)
                    ceng_nodes.append(node.val)
                    if node.left:ceng_stack.append(node.left)
                    if node.right:ceng_stack.append(node.right)
            if a%2!=0:res.append(ceng_nodes)
            else:res.append(ceng_nodes[::-1])
            a=a+1
        return res