Advent of Code 2018 Day 5

day5.scala

// https://adventofcode.com/2018/day/5

object Problem5 extends Base("input5.txt") {
  def reactPolymer(string: String): String = string.foldLeft[List[Char]](Nil) {
    case (h :: t, char) if h != char && h.toUpper == char.toUpper => t
    case (acc, char) => char :: acc
  }.mkString

  val input = lines.head

  val reduced = reactPolymer(input)

  println(s"Part 1: ${reduced.length}")

  val smallest = ('a'.toInt to 'z'.toInt).map { charInt =>
    val char = charInt.toChar
    reactPolymer(input.filter(_.toLower != char)).length
  }.min

  println(s"Part 2: $smallest")
}