Advent of Code 2022-2.scala

import java.io.FileInputStream
import scala.annotation.tailrec
import scala.io.StdIn

enum Shape:
  case rock, paper, scissors

  def winner: Shape =
    this match {
      case Shape.rock => Shape.paper
      case Shape.paper => Shape.scissors
      case Shape.scissors => Shape.rock
    }

def shapeFromAbc(text: String): Shape =
  text match {
    case "A" => Shape.rock
    case "B" => Shape.paper
    case "C" => Shape.scissors
  }

def shapeFromXyz(text: String): Shape =
    text match {
      case "X" => Shape.rock
      case "Y" => Shape.paper
      case "Z" => Shape.scissors
    }

def outcomeScore(opposite: Shape, you: Shape): Int =
  if opposite.winner == you then
    6
  else if opposite == you then
    3
  else
    0

def shapeScore(you: Shape): Int =
  you match {
    case Shape.rock => 1
    case Shape.paper => 2
    case Shape.scissors => 3
  }

def myOutcome(opposite: Shape, text: String): Shape =
  text match {
    case "X" => opposite.winner.winner
    case "Y" => opposite
    case "Z" => opposite.winner
  }

def solve2_1(values: Vector[String]): Int =
  values.map(line => {
    val Array(v0, v1) = line.split(" ")
    val opposite = shapeFromAbc(v0)
    val you = shapeFromXyz(v1)
    outcomeScore(opposite, you) + shapeScore(you)
  }).sum

def solve2_2(values: Vector[String]): Int =
  values.map(line => {
    val Array(v0, v1) = line.split(" ")
    val opposite = shapeFromAbc(v0)
    val you = myOutcome(opposite, v1)
    outcomeScore(opposite, you) + shapeScore(you)
  }).sum

@main def solve2(): Unit =
  val in = new FileInputStream("example2-2.in")
  System.setIn(in)
  val inputs = Iterator.continually(StdIn.readLine())
    .takeWhile(line => null != line)
    .toVector
  println(solve2_1(inputs))
  println(solve2_2(inputs))