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
#
class Solution:
             
    def Print(self, pRoot: TreeNode) -> List[List[int]]:
        # write code here
        if not pRoot:
            return []
        res_list = [[pRoot.val]]
        node_queue = []
        node_queue.append(pRoot.left)
        node_queue.append(pRoot.right)
        while len(node_queue) > 0:
            n_len = len(res_list)
            n_res = []
            n_node_queue = []
            for n_node in node_queue:
                if n_node:
                    if n_len % 2 == 1:
                        n_res.insert(0, n_node.val)
                    else:
                        n_res.append(n_node.val)
                    n_node_queue.append(n_node.left)
                    n_node_queue.append(n_node.right)
            node_queue = n_node_queue
            if len(n_res) > 0:
                res_list.append(n_res)
        return res_list