Given the root of a binary tree, return its maximum depth.
A binary tree's maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.
Solution:
class Solution(object):
def maxDepth(self, root):
if root is None:
return 0
else:
left_height = self.maxDepth(root.left)
right_height = self.maxDepth(root.right)
return max(left_height, right_height) + 1