PT07Z - Longest path in a tree


You are given an unweighted, undirected tree. Write a program to output the length of the longest path (from one node to another) in that tree. The length of a path in this case is number of edges we traverse from source to destination.

Input

The first line of the input file contains one integer N --- number of nodes in the tree (0 < N <= 10000). Next N-1 lines contain N-1 edges of that tree --- Each line contains a pair (u, v) means there is an edge between node u and node v (1 <= u, v <= N).

Output

Print the length of the longest path on one line.

Example

Input:
3
1 2
2 3

Output:
2

hide comments
rohit9934: 2017-05-02 07:23:45

Damn man,so many tries. I used double BFS, 1 for finding arbitrary farthest node and other from finding farthest node from that node.

prashant2018: 2017-04-20 23:23:15

getting WA on 4th test case. Can someone help please. Using double bfs

Last edit: 2017-04-21 11:02:31
gulsntils_12: 2017-04-19 12:50:51

A reminder - the answer is not the number of nodes in the path but the number of edges in it.
Got 4 WA because of it :(

ydeepak1889: 2017-03-11 15:08:43

AC in one Go! Single dfs

prasoonbatham: 2017-03-05 19:41:38

Easy two DFS :)

kingp: 2017-03-03 09:43:30

is there any need for bfs in a tree there is only one path between any two vertices so dfs is enough.

da_201501181: 2017-03-02 21:45:52

AC in one Go! Simple double dfs

gboduljak: 2017-02-15 22:24:33

should be moved to tutorial

scorpion_ajay: 2017-01-31 12:58:14

did it with both bfs and dfs, try both :)

Chisty: 2017-01-02 19:56:23

I got accepted with Adjacency Matrix in C++. bool graph[10001][10001] is okay as global variable.


Added by:Thanh-Vy Hua
Date:2007-03-28
Time limit:0.5s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
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Resource:Co-author Amber