- 24ms
- 98%
# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Solution:
def levelOrderBottom(self, root: TreeNode) -> List[List[int]]:
ans, level = [],[root]
while root and level:
ans.append([node.val for node in level])
level = [kid for node in level for kid in (node.left, node.right) if kid]
return ans[::-1]