104. Maximum Depth of Binary Tree

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.

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

def get_depth(r):
if r==None:
return 0
else:
a=get_depth(r.left)
b=get_depth(r.right)
if a>b:
b=a
return b+1
return get_depth(root)