AoC Day 2

ProblemTwo.scala

package aoc

object ProblemTwo extends App {
  println(
    (Vector(Vector(12, 2)) ++ ((0 to 100) ++ (0 to 100)).combinations(2)).map(v =>
      (
        v,
        Stream.from(0, 4).scanLeft(
          (
            scala.io.Source.fromFile("inputs/2.txt")
              .getLines
              .next
              .split(",")
              .map(_.toInt)
              .zipWithIndex
              .map(_.swap)
              .toMap ++ Map(1 -> v(0), 2 -> v(1)),
            true
          )
        )((a, i) =>
          if (a._1(i) == 99) a._1 -> false
          else if (a._1(i) == 1) a._1 ++ Map(a._1(i + 3) -> (a._1(a._1(i + 1)) + a._1(a._1(i + 2)))) -> true
          else if (a._1(i) == 2) a._1 ++ Map(a._1(i + 3) -> (a._1(a._1(i + 1)) * a._1(a._1(i + 2)))) -> true
          else sys.error("bad input")
        )
          .dropWhile(_._2)
          .head
          ._1(0)
      )
    )
      .zipWithIndex
      .flatMap(t =>
        if (t._2 == 0) Some(s"Part 1: ${t._1._2}")
        else if (t._1._2 == 19690720) Some(s"Part 2: ${100 * t._1._1(0) + t._1._1(1)}")
        else None
      )
      .take(2)
      .mkString("\n")
  )
}