META interview question

[](url)Given the root of a binary tree, return the diameter of the tree, which is the length of the longest path between any two nodes. This path can pass through the root but doesn't have to.

The length of a path between two nodes is defined by the number of edges connecting them.
[leetcode](https://leetcode.com/problems/diameter-of-binary-tree/description/)

The issue names no Java file, entry point, or test. Start by locating the repository's existing binary-tree question implementations, then use the linked LeetCode statement to confirm the expected diameter behavior. Done means the question is implemented consistently with the surrounding solutions and its expected cases are covered.

Written by the indexing model from the issue text.