Given a binary tree, you need to compute the length of the tree’s diameter. 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.

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

Constraints:

• The number of nodes in the tree is in the range $[1, 500]$.
• $-100 \leq$ Node.value $\leq 100$

So far, you’ve probably brainstormed some approaches and have an idea of how to solve this problem. Let’s explore some of these approaches and figure out which one to follow based on considerations such as time complexity and any implementation constraints.

The naive approach will be to pick one node, find the distance to every other node from the selected node, and keep track of the maximum value. Repeat this process with all the nodes of the tree. After this process, we’ll have the maximum possible distance between the two nodes. That will be the diameter of the tree.

The time complexity for the naive approach will be $O(n^2)$ ...