import scala.io.Source import scala.math.floorMod enum RPS(val score: Int): case Rock extends RPS(1) case Paper extends RPS(2) case Scissors extends RPS(3) def +(amount: Int) = RPS.fromOrdinal(floorMod(ordinal + amount, 3)) def -(amount: Int) = RPS.fromOrdinal(floorMod(ordinal - amount, 3)) def -(other: RPS) = score - other.score def vs(other: RPS) = floorMod(this - other, 3) match case 1 => 6 case 2 => 0 case _ => 3 val moveMap = Map("A"->RPS.Rock, "B"->RPS.Paper, "C"->RPS.Scissors, "X"->RPS.Rock, "Y"->RPS.Paper, "Z"->RPS.Scissors) @main def main() = val strategyGuide = Source.fromFile("day2-input").getLines.map(_.split(" ")).toArray // Can't leave it lazy as Part 1 will consume it // val strategyGuide = Source.fromString("A Y\nB X\nC Z\n").getLines.map(_.split(" ")).toArray // Part 1 - evaluate all moves in the guide using moveMap and tally score println(strategyGuide.map(movePair=> val theirMove = moveMap(movePair(0)) val ourMove = moveMap(movePair(1)) ourMove.score + (ourMove vs theirMove) ).sum) // Part 2 - X->lose, Y->draw, Z->win println(strategyGuide.map(movePair=> val theirMove = moveMap(movePair(0)) val ourMove = movePair(1) match case "X" => theirMove - 1 case "Y" => theirMove case "Z" => theirMove + 1 ourMove.score + (ourMove vs theirMove) ).sum)