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
sarvesh_19: 2016-06-16 21:44:07

famous graph problem (easy). N<=10000 array repn giving RTE and TLE...use adjacency list *only trick in this q*.

praval_singhal: 2016-05-19 16:48:16

I submitted the same code 1 hr ago. got WA. Now AC. what the F :P

Shreyans: 2016-04-13 12:46:58

Last edit: 2016-04-13 22:43:12
Ram: 2016-03-31 22:12:13

Finally got AC..!! Got WA repeatedly while using start node as 1. Changed the start node from 1 to last node and it got accepted. Please notify if there is anything wrong in my code.
http://ideone.com/sRa2d3

sharif ullah: 2016-03-14 09:47:06

just find the diameter of a tree.2 bfs.needed!!!!!!!!!!!!

rohit123456: 2016-03-05 12:28:44

done in a single dfs

newbie: 2016-01-30 14:18:18

answer is 5

newbie: 2016-01-30 14:17:44

simple dfs accepted in 0.00 s
a test case to check:
13
1 2
1 3
1 4
3 5
3 6
3 7
6 8
6 9
7 10
7 11
10 12
10 13

dwij28: 2016-01-15 06:29:00

Did it by using bfs twice, what is the dfs way of doing it ? If anyone could please provide some helpful link for solving it with dfs..

dark_lord1: 2015-12-26 00:12:43

Using a 2D matrix of type char to store edge information gives runtime error..But using adjacency list to store graph give AC....How can the 2D matrix possibly exceed memory available?? Costed me 2 RE. :(


Added by:Thanh-Vy Hua
Date:2007-03-28
Time limit:0.5s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ERL JS-RHINO NODEJS PERL6 VB.NET
Resource:Co-author Amber