A Haskell library for dealing with the dynamic connectivity problem. Consider an undirected graph, where edges may be added and removed. This library allows you to answer the question "are the nodes X and Y connected" at any point in time.
This blogpost has some more information about this library: https://jaspervdj.be/posts/2019-01-11-dynamic-graphs.html.
dynamic-graphs is available on
hackage. You can install
it using Stack, Cabal, Nix, or whichever tool you prefer.
import qualified Data.Graph.Dynamic.Levels as GD
import qualified Data.Tree as T
main :: IO ()
main = do
graph <- GD.empty'
mapM_ (GD.insert_ graph) ["Akanu", "Kanoa", "Kekoa", "Kaiwi", "Onakea"]
GD.link_ graph "Akanu" "Kanoa"
GD.link_ graph "Akanu" "Kaiwi"
GD.link_ graph "Akanu" "Onakea"
GD.link_ graph "Kaiwi" "Onakea"
GD.link_ graph "Onakea" "Kanoa"
GD.link_ graph "Kanoa" "Kekoa"
GD.connected graph "Kaiwi" "Kekoa" >>= print
GD.cut_ graph "Kaiwi" "Akanu"
GD.cut_ graph "Onakea" "Akanu"
GD.cut_ graph "Onakea" "Kanoa"
GD.connected graph "Kaiwi" "Kekoa" >>= print
GD.link_ graph "Akanu" "Kaiwi"
GD.connected graph "Kaiwi" "Kekoa" >>= print