import scala.io.Source import scala.math.floorMod extension (i: Int) def %%(modulus: Int) = floorMod(i, modulus) 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((ordinal + amount) %% 3) def -(amount: Int) = RPS.fromOrdinal((ordinal - amount) %% 3) def -(other: RPS) = score - other.score def vs(other: RPS) = (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("input/2").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)