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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lm10_piyush:
20200802 22:56:09
AC in one go, dp on trees. 

amitk766:
20200707 15:56:58
Run dfs/bfs two times , in the first run find the farthest vertex from vert 1, and the again run dfs from that vertex(farthest) and calculate the longest path. 

sarveshjain967:
20200625 13:37:47
AC in one go. Remember what constitutes the longest path:


zegatron:
20200622 20:37:33
Do not print a new line at the end of the ans. 

zegatron:
20200622 20:35:21
I am getting wrong answer on my code. I call bfs for each node. and take the maximum depth. 

saurabhshadow:
20200529 20:42:24
If you still stuck at this:


nature95:
20200514 13:03:23
Used bfs two times.


offamitkumar:
20200504 19:33:55
AC in single graph traversal . Just keep track of 3 things :


gnuzinhoo:
20200502 16:05:00
I solved it using two bfs 

yourmom__:
20200423 08:18:56
Java people, Scanner wont cause TLE in this question. I used scanner and got AC. 
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 