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.


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).


Print the length of the longest path on one line.


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scolar_fuad: 2019-09-04 06:04:59

Simple dfs problem ...
easy one for beginner...

Happy coding

jame___boy: 2019-08-30 00:30:33

many many thanx @anand_undavia for sharing the link.......
...... really helpful :-D

Last edit: 2019-08-30 00:32:01
hetp111: 2019-08-24 05:04:07

2 dfs:
Start from any node and find the farthest node (say x), now again do a dfs from x and find the farthest node (say y), the answer is distance between x and y.

Last edit: 2019-08-24 05:04:21
sonianand966: 2019-08-21 15:08:26

Did it using 2-bfs method however was a difficult one as an all new question!

manas_uchiha10: 2019-08-19 15:58:37

AC in one go!!

elzahaby: 2019-08-14 22:05:54

using 2 BFS can't do it with DFS acctually idk why xD

rockstar_786: 2019-07-05 22:15:49

@sarthak_1998 bro i was getting the same its due to small memory allocation of declared array.
You are doing a mistake like this : ---->
int arr[2000][2000];
int a = arr[2001] [2000];

You can read one of the answers here.

an09mous: 2019-07-03 12:12:10

We can precompute heights of all the sub-trees in an array for faster computation

shahayush457: 2019-07-02 09:37:56

Just use 2 dfs :)

sarthak_1998: 2019-06-26 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.

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