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 right_order(self , lay: list[TreeNode]):
        next_lay = []
        now_res = []
        for tmp in lay:
            now_res.append(tmp.val)
            if tmp.right:
                next_lay.insert(0,tmp.right)
            if tmp.left:
                next_lay.insert(0,tmp.left)
        return next_lay, now_res

    def left_order(self , lay: list[TreeNode]):
        next_lay = []
        now_res = []
        for tmp in lay:
            now_res.append(tmp.val)
            if tmp.left:
                next_lay.insert(0,tmp.left)
            if tmp.right:
                next_lay.insert(0,tmp.right)
        return next_lay, now_res

    def Print(self , pRoot: TreeNode) -> List[List[int]]:
        if not pRoot:
            return []
        res = []
        lay = [[pRoot]]
        i = 0
        while lay:
            nowlay = lay.pop(0)
            if i%2 == 0:
                next_lay, now_res = self.left_order(nowlay)
                if next_lay:
                    lay.append(next_lay)
                res.append(now_res)
            else:
                next_lay, now_res = self.right_order(nowlay)
                if next_lay:
                    lay.append(next_lay)
                res.append(now_res)
            i += 1
        return res