2024-08 Scala 2

scala2/src/main/resources/2024/08-test-00.txt

@@ -1 +1,12 @@
-noop
+............
+........0...
+.....0......
+.......0....
+....0.......
+......A.....
+............
+............
+........A...
+.........A..
+............
+............

scala2/src/main/resources/2024/08.txt

@@ -1 +1,50 @@
-noop
+....h.....Q..............Y........................
+...............................Y........C.........
+...............m..........x................B......
+........................Y..............qB.........
+......g4.........................h..Y.....q...c...
+................n.....R...........................
+.......................................w........5.
+........g...m...........................w5........
+..n...........R.1................W.......q.5......
+.........h...n.................e..................
+...............................R..........B....C..
+.........4................................5.e.....
+.......0..4......n.......x..w.....................
+.......g.....m........x..b.....W.....B.......w....
+..............m........................3......C...
+........q...0.......h....................C.3......
+..................3.....................D.........
+...............R..........3.............X.........
+..............................W............k2.....
+..........7............................2..........
+...............A.............................X...2
+.......................c...x......................
+....................................d.............
+.....1......................d.....................
+...........1...........................e..........
+.........0.7K.........................2.........W.
+...b......0.....A.................................
+......................1....ic.....................
+......b......................i....................
+..Q.....b..........................A..E...........
+...7.........................V....................
+........A.....................v......d............
+........v............c...................8E.......
+..............................V........8.....E..N.
+......................6...........................
+.......I....M....................V................
+...G......................a.......8...............
+.........r.9........a...i..................X......
+...............r..i...............e............N..
+.....H...........k....9.....6...............8.....
+.v.....................6................V.........
+.........v.......a........k..........D............
+Ha..........k.........K........E.......d..........
+...............y.MG..............6....D...........
+.........H..G...M......9.K..............N.........
+.......G.........................K................
+...............M.........I.......D................
+..................................................
+....r....y................9.......................
+....y................................N............

scala2/src/main/scala/jurisk/adventofcode/y2024/Advent08.scala

@@ -1,37 +1,111 @@
 package jurisk.adventofcode.y2024
 
+import cats.implicits._
+import jurisk.adventofcode.y2024.Advent08.Square.Antenna
+import jurisk.adventofcode.y2024.Advent08.Square.Empty
+import jurisk.geometry.Coords2D
+import jurisk.geometry.Field2D
 import jurisk.utils.FileInput._
-import jurisk.utils.Parsing.StringOps
+import mouse.all._
+
+import scala.annotation.tailrec
 
 object Advent08 {
-  type Input = List[Command]
-  type N     = Long
-
-  sealed trait Command extends Product with Serializable
-  object Command {
-    case object Noop                      extends Command
-    final case class Something(
-      values: List[N]
-    ) extends Command
-    final case class Other(value: String) extends Command
-
-    def parse(s: String): Command =
-      s match {
-        case "noop"            => Noop
-        case s"something $rem" => Something(rem.extractLongList)
-        case s if s.nonEmpty   => Other(s)
-        case _                 => s.failedToParse
-      }
+  private type Frequency = Char
+
+  sealed trait Square
+  object Square {
+    case object Empty                              extends Square
+    final case class Antenna(frequency: Frequency) extends Square
+
+    def parse(ch: Char): Square = ch match {
+      case '.' => Empty
+      case ch  => Antenna(ch)
+    }
   }
 
+  private type SquareAndAntiNodes = (Square, Set[Frequency])
+  type Input                      = Field2D[SquareAndAntiNodes]
+  type N                          = Long
+
   def parse(input: String): Input =
-    input.parseLines(Command.parse)
+    Field2D.parseCharField(input).map(ch => (Square.parse(ch), Set.empty))
+
+  @tailrec
+  private def helper(
+    field: Input,
+    frequency: Char,
+    current: Coords2D,
+    diff: Coords2D,
+    limit: Option[Int],
+    count: Int = 0,
+  ): Input =
+    if (field.isValidCoordinate(current) && limit.forall(count <= _)) {
+      val updated = if (limit.isEmpty || count != 0) {
+        field.modifyIgnoringInvalidCoords(
+          current,
+          { case (ch, set) =>
+            (ch, set + frequency)
+          },
+        )
+      } else {
+        field
+      }
+
+      helper(updated, frequency, current + diff, diff, limit, count + 1)
+    } else {
+      field
+    }
+
+  private def update(
+    field: Input,
+    frequency: Char,
+    a: Coords2D,
+    b: Coords2D,
+    limit: Option[Int],
+  ): Input =
+    List((a, a - b), (b, b - a)).foldLeft(field) {
+      case (field, (start, diff)) =>
+        helper(field, frequency, start, diff, limit)
+    }
+
+  private def processFrequency(
+    field: Input,
+    frequency: Char,
+    limit: Option[Int],
+  ): Input = {
+    val locations = field.filterCoordsByValue { case (sq, _) =>
+      sq == Antenna(frequency)
+    }
+    val pairs     = (locations, locations).mapN { case (a, b) =>
+      (a != b).option((a, b))
+    }.flatten
+
+    pairs.foldLeft(field) { case (field, (a, b)) =>
+      update(field, frequency, a, b, limit)
+    }
+  }
+
+  def solve(data: Input, limit: Option[Int]): N = {
+    val frequencies = data.values.flatMap { case (sq, _) =>
+      sq match {
+        case Antenna(frequency) => Some(frequency)
+        case Empty              => None
+      }
+    }.toSet
+
+    val result = frequencies.foldLeft(data) { case (field, frequency) =>
+      processFrequency(field, frequency, limit)
+    }
+
+    result.count { case (_, s) => s.nonEmpty }
+  }
 
   def part1(data: Input): N =
-    0
+    solve(data, 1.some)
 
   def part2(data: Input): N =
-    0
+    solve(data, none)
 
   def parseFile(fileName: String): Input =
     parse(readFileText(fileName))

scala2/src/test/scala/jurisk/adventofcode/y2024/Advent08Spec.scala

@@ -10,21 +10,21 @@ class Advent08Spec extends AnyFreeSpec {
 
   "part 1" - {
     "test" in {
-      part1(testData) shouldEqual 0
+      part1(testData) shouldEqual 14
     }
 
     "real" in {
-      part1(realData) shouldEqual 0
+      part1(realData) shouldEqual 256
     }
   }
 
   "part 2" - {
     "test" in {
-      part2(testData) shouldEqual 0
+      part2(testData) shouldEqual 34
     }
 
     "real" in {
-      part2(realData) shouldEqual 0
+      part2(realData) shouldEqual 1005
     }
   }
 }