104. Maximum Depth of Binary Tree.py

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None


class Solution:
    def maxDepth(self, root):
        return (1 + max(self.maxDepth(root.left), self.maxDepth(root.right))) if root else 0