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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rockstar_786:
20190705 22:15:49
@sarthak_1998 bro i was getting the same its due to small memory allocation of declared array.


an09mous:
20190703 12:12:10
We can precompute heights of all the subtrees in an array for faster computation 

shahayush457:
20190702 09:37:56
Just use 2 dfs :) 

sarthak_1998:
20190626 17:26:59
My code is giving runtime error (SIGSEGV) however it is giving right answer on every test case I tried. Please, someone, help me.


anand_undavia:
20190615 19:27:03
This helped me a lot: https://www.youtube.com/watch?v=w9vjFB7m0PM


cenation007:
20190603 17:01:17
take any node as root, start with root to find longest path


arunkumarreddy:
20190602 20:16:54
i have submitted solutions for 2 problems on graphs today. I got NZEC error for both the problems, can someone help me understand why i am getting that error. If you want i can share my code with you. 

klmo:
20190425 15:38:38
1 DFS. finally ac in java. 

klmo:
20190425 13:45:49
2 dfs operation with tree in adjacency matrix is giving TLE in java. Using BufferedReader. Any suggestion?


brijraj:
20190217 11:54:05
@suvro_coder your input is wrong. There are 7 nodes instead of 6. Otherwise it will not add edge from 6 to 7 
Added by:  ThanhVy Hua 
Date:  20070328 
Time limit:  0.5s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ERL JSRHINO NODEJS PERL6 VB.NET 
Resource:  Coauthor Amber 