Diameter of Binary Tree - Better Design

Question

I have written a code for finding diameter of Binary Tree. Need suggestions for the following:

1. Can I do this without using static variable at class level?

Answer 1

The most efficient way is to compute diameter along with height to get to O(n) and here is the easiest way to get so [Python3,PyPy3]

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

class Solution:
def diameterOfBinaryTree(self, root: TreeNode) -> int:
    self.height = 1

    def height(node):
        if node is None:
            return 0
        l_height = height(node.left)
        r_height = height(node.right)
        self.height = max(self.height,l_height+r_height+1)
        return max(l_height,r_height) + 1

    height(root)
    return self.height-1

The most simplest and affordable solution with faster runtime and lower complexity.