Return Type of Kosaraju Proposal

[ZigRazor]

I'm still not completely convinced about the return type though. Specifically:

• Wouldn't it be better if the returned connected components contained pointers to the vertex in the graph, instead of (subgraph) copies? I mean, if one wants to check which component a given vertex of the graph belongs to, I think it would make more sense to refer to vertices in the original graph than to vertices in a graph isomorphic/identical to the original. But this question applies to other algorithms in the library too (e.g. BFS, DFS). In some cases (e.g. Max flow, MST algorithms) we return vectors of pairs of strings for the edges, why don't we return vectors of pointers to edges instead? I general, I feel that the interface is a bit too heterogeneous concerning algorithms returns type.

• With this choice of data structure (i.e. std::vector) it is kind of hard to get the strongly connected component for a given vertex (linear time search). Maybe doing something like what has been done for DialResult (i.e. unordered_map) could simplify this. And providing hashing for single vertices is not really a problem since they already have an id attribute.

Originally posted by @dvd2000 in #260 (comment)

[guru2396]

Hello. The new return type of this algorithm should be the one suggested as below??

I took a look at the approach used in the Boost graph library and they are using a map with vertices as keys and distinct labels for every strongly connected component as values. We can maybe do something similar here? But I think it would be important to keep consistency with the rest of the library.

Originally posted by @dvd2000 in #251

[ZigRazor]

Yes, we can do something similar in this library

[guru2396]

okay. Can I take this up?

[ZigRazor]

sure

[guru2396]

@ZigRazor, one more thing that can be modified. I think the adjacency matrix can be used to populate the nodeSet in getNodeSet() method instead of using edgeSet. This method is used many times in the code, so may be there can be some benefit.

[ZigRazor]

@ZigRazor, one more thing that can be modified. I think the adjacency matrix can be used to populate the nodeSet in getNodeSet() method instead of using edgeSet. This method is used many times in the code, so may be there can be some benefit.

Yes @guru2396 but open a new issue for this improvement

[guru2396]

okay sure, will open