python3题解 | #求二叉树的层序遍历#

import collections
# 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 root TreeNode类 
# @return int整型二维数组
#
class Solution:
    def levelOrder(self , root: TreeNode) -> List[List[int]]:
        # write code here
        if not root: return []
        res = []
        hhh = collections.deque([root])
        while hhh:
            ceng = []
            for _ in range(len(hhh)):
                cur = hhh.popleft()
                ceng.append(cur.val)
                if cur.left:
                    hhh.append(cur.left)
                if cur.right:
                    hhh.append(cur.right)
            res.append(ceng)
        return res