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
hide comments
vedang:
20151225 18:23:38
Don't know why but when I changed memset to fill_n in my C++ code, WA turned into AC! 

the_sage:
20151218 11:30:44
the tree should not have a cycle but the test cases have a cycle in them for example


the_sage:
20151218 11:18:19
for the test case


codelover25:
20151217 16:36:48
AC in 1 go :) Just be careful with ordering of tree. 

piyush9620:
20151215 11:20:08
http://www.spoj.com/users/markroxor


maverick_10:
20151213 11:59:00
Ooh, finally I am learnig graphs!!!


bunnycoder:
20151212 08:42:09
Be careful with the line one node to another costed me 1 WA simple dfs


Shantanu Banerjee:
20151202 09:20:10
@Mohit Rathore The input will not be a forest.


Akshay Damle:
20151027 23:14:53
AC in 1 go :) This Quora answer was helpful: https://www.quora.com/Howdoesfollowingalgorithmforfindinglongestpathintreework 

satish9040:
20151027 15:06:14
http://apps.topcoder.com/forums/?module=Thread&threadID=794604&start=0&mc=3#1758019 
Added by:  ThanhVy Hua 
Date:  20070328 
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