Diameter of a Tree

Difficulty: 1600 4000 ms 128 MB

bfs trees

Print the diameter of the tree: the number of edges on the longest path between any two nodes.

Input: the first line has N; each of the next N−1 lines has an edge u v.

Output: the diameter.

Constraints:

• 1 ≤ N ≤ 10⁵

Sample Tests

5
1 2
2 3
2 4
4 5

3

1

0

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