# DIAMETER OF BINARY TREE | CLEAN CODE | RECURSION | PROGRAMMING

By: Saurav

2018-04-02 02:48:00 UTC

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.

This problem is more of a trivial problem.

As per geeks for geeks:

The diameter of a tree T is the largest of the following quantities:

* the diameter of T’s left subtree
* the diameter of T’s right subtree
* the longest path between leaves that goes through the root of T (this can be computed from the heights of the subtrees of T)

```def diameter_of_binary_tree(root)
return 0 if !root

lheight = height(root.left)
rheight = height(root.right)

return [lheight+rheight, [diameter_of_binary_tree(root.left), diameter_of_binary_tree(root.right)].max].max
end

def height(root)
return 0 if !root
return 1 + [height(root.left), height(root.right)].max
end ```