Maximum Depth of Binary Tree——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.

 

# 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
        maxDepth = -1
        if root.left != None:
            maxDepth = max(maxDepth, self.maxDepth(root.left)+1)
        if root.right != None:
            maxDepth = max(maxDepth, self.maxDepth(root.right)+1)
        if root.right == None and root.left == None:
            return 1
        return maxDepth