Diameter of Binary Tree.md

Given a binary tree, you need to compute the length of the diameter of the tree. The diameter of a binary tree is the length of the longest path between any two nodes in a tree. This path may or may not pass through the root.

Example:
Given a binary tree 
          1
         / \
        2   3
       / \     
      4   5    
Return 3, which is the length of the path [4,2,1,3] or [5,2,1,3].

Note: The length of path between two nodes is represented by the number of edges between them.

My code:

# 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 diameterOfBinaryTree(self, root):
        """
        :type root: TreeNode
        :rtype: int
        """
        if root==None:
            return 0
        self.max_diameter=0
        self.diameterOfBinaryTree1(root)
        return self.max_diameter-1
    def diameterOfBinaryTree1(self, root):
        #First return the diameter,2nd return the depth
        if root==None:
            return 0
        count1=self.diameterOfBinaryTree1(root.left)
        count2=self.diameterOfBinaryTree1(root.right)
        if count1+count2+1>self.max_diameter:
            self.max_diameter=count1+count2+1
        #print('%d root, depth %d'%(root.val,max(count1,count2)+1))
        return max(count1,count2)+1
        

Solution: https://leetcode.com/problems/diameter-of-binary-tree/