refactor(day23): clean up

Author: fdlk

day23.sc

@@ -1,35 +1,10 @@
 case class Connection(room: Char, hallway: Char, distance: Int, blockedBy: String)
 
-val connectionList = List(
-  Connection('A', '0', 2, "1"),
-  Connection('A', '1', 1, ""),
-  Connection('A', '2', 1, ""),
-  Connection('A', '3', 3, "2"),
-  Connection('A', '4', 5, "23"),
-  Connection('A', '5', 7, "234"),
-  Connection('A', '6', 8, "2345"),
-  Connection('B', '0', 4, "21"),
-  Connection('B', '1', 3, "2"),
-  Connection('B', '2', 1, ""),
-  Connection('B', '3', 1, ""),
-  Connection('B', '4', 3, "3"),
-  Connection('B', '5', 5, "34"),
-  Connection('B', '6', 6, "345"),
-  Connection('C', '0', 6, "321"),
-  Connection('C', '1', 5, "32"),
-  Connection('C', '2', 3, "3"),
-  Connection('C', '3', 1, ""),
-  Connection('C', '4', 1, ""),
-  Connection('C', '5', 3, "4"),
-  Connection('C', '6', 4, "45"),
-  Connection('D', '0', 8, "4321"),
-  Connection('D', '1', 7, "432"),
-  Connection('D', '2', 5, "43"),
-  Connection('D', '3', 3, "4"),
-  Connection('D', '4', 1, ""),
-  Connection('D', '5', 1, ""),
-  Connection('D', '6', 2, "5"),
-)
+val connectionList = common.loadPackets(List("day23.txt")).map(_.split(" ").toList match {
+  case room :: hall :: distance :: obstructedBy =>
+    Connection(room.charAt(0), hall.charAt(0), distance.toInt, obstructedBy.mkString)
+})
+
 // (room, hallway) -> Connection
 val connections: Map[(Char, Char), Connection] =
   connectionList.groupBy(c => (c.room, c.hallway)).view.mapValues(_.head).toMap
@@ -57,20 +32,19 @@ case class State(rooms: Map[Char, String], hallways: Map[Char, Option[Char]] = h
     State(rooms.updated(room, contents.tail), hallways.updated(hallway, Some(contents.head)))
   }
 
-  def moveFromHallwayToRoom(hallway: Char, room: Char): State = {
-    assert(hallways(hallway).isDefined)
+  def moveFromHallwayToRoom(hallway: Char, room: Char): State =
     State(rooms.updated(room, room + rooms(room)), hallways.updated(hallway, None))
-  }
 }
 
 class Burrow(depth: Int) extends common.Grid[State] {
+  val goal = State(rooms.map(room => room -> room.toString * 2).toMap)
+
   override def heuristicDistance(from: State, to: State): Int =
     from.rooms.flatMap {
       case (room, contents) => contents.filter(_ != room).map(mobility)
     }.sum * 4 +
       from.hallways.map {
-        case (hallway, Some(amphipod)) =>
-          connections((amphipod, hallway)).distance * mobility(amphipod)
+        case (hallway, Some(amphipod)) => connections((amphipod, hallway)).distance * mobility(amphipod)
         case _ => 0
       }.sum
 
@@ -90,27 +64,22 @@ class Burrow(depth: Int) extends common.Grid[State] {
       }
 
   override def moveCost(from: State, to: State): Int = {
-    val hallwayOption = halls.find(hallway => from.hallways(hallway) != to.hallways(hallway))
-    assert(hallwayOption.isDefined)
-    val hallway = hallwayOption.get
+    val hallway = halls.find(hallway => from.hallways(hallway) != to.hallways(hallway)).get
     if (from.hallways(hallway).isEmpty) {
       // moved from room to hallway
       val room = rooms.find(room => from.rooms(room) != to.rooms(room)).get
       val extraSteps = depth - to.rooms(room).length
       val aphipod = to.hallways(hallway).get
       (connections((room, hallway)).distance + extraSteps) * mobility(aphipod)
     } else {
-      val source = from.hallways(hallway)
-      assert(source.isDefined)
       // moved from hallway to room
-      val aphipod = source.get
+      val aphipod = from.hallways(hallway).get
       val extraSteps = depth - from.rooms(aphipod).length
       (connections((aphipod, hallway)).distance + extraSteps) * mobility(aphipod)
     }
   }
 }
 
-val burrowPart1 = new Burrow(1)
 val inputPart1 = State(Map('A' -> "CB", 'B' -> "BC", 'C' -> "DA", 'D' -> "DA"))
 /*
 #############

src/main/resources/day23.txt

@@ -0,0 +1,28 @@
+A 0 2 1
+A 1 1
+A 2 1
+A 3 3 2
+A 4 5 23
+A 5 7 234
+A 6 8 2345
+B 0 4 21
+B 1 3 2
+B 2 1
+B 3 1
+B 4 3 3
+B 5 5 34
+B 6 6 345
+C 0 6 321
+C 1 5 32
+C 2 3 3
+C 3 1
+C 4 1
+C 5 3 4
+C 6 4 45
+D 0 8 4321
+D 1 7 432
+D 2 5 43
+D 3 3 4
+D 4 1
+D 5 1
+D 6 2 5