Given an undirected tree, return its diameter: the number of edges in a longest path in that tree.
The tree is given as an array of edges where edges[i] = [u, v] is a bidirectional edge between nodes u and v. Each node has labels in the set {0, 1, ..., edges.length}.
Example 1:
Input: edges = [[0,1],[0,2]] Output: 2 Explanation: A longest path of the tree is the path 1 - 0 - 2.
Example 2:
Input: edges = [[0,1],[1,2],[2,3],[1,4],[4,5]] Output: 4 Explanation: A longest path of the tree is the path 3 - 2 - 1 - 4 - 5.
Constraints:
0 <= edges.length < 10^4edges[i][0] != edges[i][1]0 <= edges[i][j] <= edges.length- The given edges form an undirected tree.