Advent of Code 2017 - Day1

aoc2017D1.scala

  def simpleCaptcha(_source: String) = {
    (_source + _source.head).map(_.asDigit).sliding(2).collect { case Seq(a, b) if a == b => a }.sum
  }

  def advancedCaptcha(_source: String) = {
    val size = _source.length / 2
    val (firstHalf, lastHalf) = _source.map(_.asDigit).splitAt(size)
    firstHalf.zip(lastHalf).collect { case (e1, e2) if e1 == e2 => e1 }.sum * 2
  }