This is the problem 107 from the Project Euler. Initially I did this algorithm as part of a HackerRank challenge. It is an implementation of the Prim's algorithm for finding the minimum weight spanning tree on an un-directed graph that connects the vertices via weighted edges:
Because the implementation is not very well explained in Wikipedia (difficult to follow), for the second version of the algorithm I followed as an example the C++ implementation of this algorithm
at Stephan Brumme's page
and did it in Java aiming to improve my Java skills
The input & output are read from a file, and format is as described in HackerRank:
First line, consists of two numbers - the number of nodes and the number of edges respectively.
The next N number of lines consists of three numbers - the edge represented as start and finish node and the weight:
The output is a single number - the sum of the total weight of the resulting graph:
15
There is a compiled file called minimal-network.jar which you can run using the following command:
java -jar minimal-network.jar data.txt