Diameter of Binary Tree

Easy

Given the root of a binary tree, return the length of its diameter — the number of edges on the longest path between any two nodes (the path may not pass through the root).

Example 1

Input:  root = [1,2,3,4,5]
Output: 3

Example 2

Input:  root = [1,2]
Output: 1

Constraints

• 1 <= number of nodes <= 10^4
• -100 <= Node.val <= 100