ChargingChaos.scala

object ChargingChaos extends App {

  def minMove(inputs: Seq[String]): Option[Int] = {
    
    def runLength(s: String) = (List.empty[(Char, Int)] /: s) {
      case ((c, n) :: tail, char) if c == char =>
        (c, n + 1) :: tail
      case (acc, char) =>
        (char, 1) :: acc
    }.reverse.unzip

    val (chars, lengths) = (inputs map runLength).unzip
    if (chars.toSet.size > 1) None
    else Some {
      (List.fill(lengths.head.size)(List.empty[Int]) /: lengths) {
        _ zip _ map { case (acc, x) => x :: acc }
      }.map { acc =>
        val diff = acc.toVector.sorted
        val median = diff(diff.size / 2)
        diff.map(math abs _ - median).sum
      }.sum
    }
    
  }

  def process(iter: Iterator[String])(out: String => Unit) =
    for (i <- 1 to iter.next().toInt) {
      val n = iter.next().toInt
      val input = Seq.fill(n)(iter.next())
      out(s"Case #$i: ${minMove(input) getOrElse "Fegla Won"}")
    }

  import java.io._
  val out = new PrintStream(new File("a.out"))
  try {
    process(io.Source.fromFile("A-large-practice.in").getLines) { s: String =>
      out.println(s)
    }
  } finally {
    out.flush; out.close
  }

}