Advent of Code 2022-10.scala

import java.io.FileInputStream
import scala.annotation.{tailrec, targetName}
import scala.io.StdIn
import scala.math.abs

sealed trait Command {
  def cycle: Int
}
case object Noop extends Command {
  def cycle = 1
}
case class AddX(x: Int) extends Command {
  def cycle = 2
}

case class Cpu(register: Int, command: Command, cycle: Int)

def simulate(acc: Vector[Cpu], commands: Vector[Command]): Vector[Cpu] =
  acc.last match
    case cpu@Cpu(_, _, cycle) if 1 < cycle =>
      simulate(acc :+ cpu.copy(cycle = cycle - 1), commands)
    case cpu@Cpu(register, cpuCommand, _) =>
      val nextCpu = cpuCommand match {
        case Noop =>
          cpu
        case AddX(x) =>
          cpu.copy(register = register + x)
      }
      commands.headOption match
        case Some(command) =>
          simulate(acc :+ nextCpu.copy(command = command, cycle = command.cycle), commands.tail)
        case _ =>
            acc

def solve10_1(commands: Vector[Command]): Int =
  val cpu = Cpu(1, commands.head, commands.head.cycle)
  val result = simulate(Vector(cpu), commands.tail)
  Vector(20, 60, 100, 140, 180, 220).map(idx => result(idx - 1).register * idx).sum


def solve10_2(commands: Vector[Command]): String =
  val cpu = Cpu(1, commands.head, commands.head.cycle)
  val result = simulate(Vector(cpu), commands.tail)
  val printed = (0 until 240).flatMap { idx =>
    val width: Int = 40
    val centerX = result(idx).register
    val c: String = if 1 >= abs(centerX - (idx % width)) then "#" else "."
    if idx % width == width - 1 then
      c + "\n"
    else
      c
  }
  printed.mkString


@main def solve10(): Unit =
  val in = new FileInputStream("example10-2.in")
  System.setIn(in)
  val inputs = Iterator.continually(StdIn.readLine())
    .takeWhile(line => null != line)
    .map(_.split(" ") match
      case Array("addx", v) => AddX(v.toInt)
      case _ => Noop
    )
    .toVector
  println(solve10_1(inputs))
  println(solve10_2(inputs))