Java: how to represent graphs?

Question

I\'m implementing some algorithms to teach myself about graphs and how to work with them. What would you recommend is the best way to do that in Java? I was thinking somethi

Answer 1

If you need weighted edges and multigraphs, you might want to add another class Edge.

I would also recommend using generics to allow specifying which sub-class of Vertex and Edge are currently used. For example:

public class Graph {
List vertices;
...
}

When it comes to implementing graph algorithms, you could also define interfaces for your graph classes on which the algorithms can operate, so that you can play around with different implementations of the actual graph representation. For example, simple graphs that are well-connected might be better implemented by an adjacency matrix, sparser graphs might be represented by adjacency lists - it all depends...

BTW Building such structures efficiently can be quite challenging, so maybe you could give us some more details on what kind of job you would want to use them for? For more complex tasks I would suggest you have a look at the various Java graph libraries, to get some inspiration.