Scala3
all done!
def parseLine(a: String): List[UnDiEdge[String]] = a match
case s"$n: $r" => r.split(" ").map(_ ~ n).toList
case _ => List()
def removeShortestPath(g: Graph[String, UnDiEdge[String]], ns: List[String]) =
g.removedAll(g.get(ns(0)).shortestPathTo(g.get(ns(1))).map(_.edges.map(_.outer)).getOrElse(List()))
def removeTriple(g: Graph[String, UnDiEdge[String]], ns: List[String]) =
List.fill(3)(ns).foldLeft(g)(removeShortestPath)
def division(g: Graph[String, UnDiEdge[String]]): Option[Long] =
val t = g.componentTraverser()
Option.when(t.size == 2)(t.map(_.nodes.size).product)
def task1(a: List[String]): Long =
val g = Graph() ++ a.flatMap(parseLine)
g.nodes.toList.combinations(2).map(a => removeTriple(g, a.map(_.outer))).flatMap(division).take(1).toList.head