104-maximum-depth-of-binary-tree.py

'''
Given a binary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from the root 
node down to the farthest leaf node.
'''

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

class Solution(object):
	def maxDepth(self, root):
		"""
		:type root: TreeNode
		:rtype: int
		"""

		if root == None:
			return 0

		leftDepth = 1 + self.maxDepth(root.left)
		rightDepth = 1 + self.maxDepth(root.right)

		return max(leftDepth, rightDepth)