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 N1 lines contain N1 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
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xopxop1:
20170818 13:20:05
Solution to this and many other tasks are here http://xoptutorials.com/index.php/category/spoj/ 

sharma96:
20170815 22:05:04
Can anyone please tell how to handle this test case:


Shantanu Banerjee:
20170808 08:44:15
Simple Double DFS! 

sunidhi:
20170804 06:17:12
@anuraag19 spoj won't allow us to see your solution.use some other platform to share your code.


anuraag19:
20170802 18:51:15
does anybody know why i am getting runtime error?


karthik_vg:
20170718 13:55:21
dfs + memorization ;) 

sagnik_66:
20170705 10:48:57
Solved using single DFS, this helped : https://cptalks.quora.com/DiameterofaTree 

phben:
20170704 03:24:22
@prashant2018 How to see the test cases? Aren't they hidden? 

ashwani0605:
20170621 06:52:03
Some of the answer in SPOJ toolkit are wrong, so verify on your own 

sandeep_4141:
20170614 10:27:13
dfs 
Added by:  ThanhVy Hua 
Date:  20070328 
Time limit:  0.181s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ERL JSRHINO NODEJS PERL6 VB.NET 
Resource:  Coauthor Amber 