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
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sandeep_4141:
2017-06-14 10:27:13
dfs |
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rahul_nitdgp:
2017-06-06 09:02:40
Only one DFS! |
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Anirban Acharya:
2017-06-05 07:56:21
how do you get the root node in these kind of problems on Spoj? For this problem I considered the first node as the root node although any node can be considered as the root for finding the deepest node, but I am asking in general. |
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swas99:
2017-05-20 10:48:15
Weak test-cases.
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Rajat Gautam:
2017-05-18 23:09:07
@prashant2018 Use first bfs to find farthest node. and second bfs starting from this node to find longest path. |
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helloitsme:
2017-05-03 21:36:54
I used bfs twice with adjacency list in JAVA ,then tried dfs twice but still its timing out :( , Please help! |
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rohit9934:
2017-05-02 07:23:45
Damn man,so many tries. I used double BFS, 1 for finding arbitrary farthest node and other from finding farthest node from that node. |
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prashant2018:
2017-04-20 23:23:15
getting WA on 4th test case. Can someone help please. Using double bfs Last edit: 2017-04-21 11:02:31 |
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gulsntils_12:
2017-04-19 12:50:51
A reminder - the answer is not the number of nodes in the path but the number of edges in it.
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ydeepak1889:
2017-03-11 15:08:43
AC in one Go! Single dfs |
| 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 |
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