题解 | 把二叉树打印成多行

from sre_compile import CATEGORY_UNI_NOT_WORD
# 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 []
        ans, s = [], [pRoot]
        while s:#二叉树层序遍历加上每层计数
            cur, n = [], len(s)
            for _ in range(n):
                p = s.pop(0)
                cur.append(p.val)
                if p.left:
                    s.append(p.left)
                if p.right:
                    s.append(p.right)
            ans.append(cur)
        return ans