Expose sets of reachable vertices in ShortestPathAllPairs.Result

[UnasZole]

Hi,

Currently, the ShortestPathAllPairs.Result exposes only a getPath method that allows retrieving the shortest path between two known vertices - and the method returns null if there is no path.

But after running an APSP algorithm, we should have access to two other pieces of information :

• The set of target vertices reachable from a given source vertex. (Given "S", get the set of "T" such that getPath(S,T) is not null)
• The set of source vertices that a given target vertex is reachable from (reciprocally, given "T", the set of S such that getPath(S,T) is not null)

With the current API, the only way to get the information is to loop on all vertices of the graph and filter them, which feels quite inefficient in a large graph - whereas the APSP result already contains this information internally and could probably expose it in a much more efficient manner.

Would it be possible to add these two methods to the ShortestPathAllPairs.Result ?

• Set listReachableTargets(vertex)
• Set listReachableSources(vertex)