Rotate.scala

object Rotate extends App {
  def pushRight(line: String): String = {
    // gravity from right side
    // same as rotate clock wise and gravity from bottom
    val N = line.size
    val dotRemoved = line.replace(".", "")
    val dots = "." * (N - dotRemoved.size)
    dots + dotRemoved
  }
  
  def getWinners(line: String, K: Int): Set[Char] = {
    // get winner character from a line
    val kLengthSublines = line.sliding(K)
    val winnerChars = kLengthSublines.map(_.toSet).filter(_.size == 1)
    winnerChars.flatten.filter(_ != '.').toSet
  }
  
  def makeCols(lines: List[String]): List[String] = {
    // make list of column(vertical) lines
    val N = lines(0).size
    (for (i <- 0 until N) yield lines.map(_(i)).mkString).toList
  }
  
  def makeDiags(lines: List[String]): List[String] = {
    // make list of diagonal lines
    // ABC     ..ABC.. ==> topLeftToBottomRight: ..G .DH AEI BF. C..
    // DEF ==> ..DEF..
    // GHI     ..GHI.. ==> topRightToBottomLeft: ..I .FH CEG BD. A..
    val N = lines(0).size
    val dotWrappedLines = lines.map ("." * (N - 1) + _ + "." * (N - 1))
    val topLeftToBottomRight = for (i <- 0 until 2 * N - 1) yield {
      (for (j <- 0 until N) yield dotWrappedLines(j)(i + j)).mkString
    }
    val topRightToBottomLeft = for (i <- 3 * N - 3 to N - 1 by -1) yield {
      (for (j <- 0 until N) yield dotWrappedLines(j)(i - j)).mkString
    }
    (topLeftToBottomRight ++ topRightToBottomLeft).toList
  }
  
  def solve(lines: List[String], K: Int): String = {
    val pushedLines = lines map pushRight
    val pushedCols = makeCols(pushedLines)
    val pushedDiags = makeDiags(pushedLines)
    val all = pushedLines ++ pushedCols ++ pushedDiags
    val winners = all.map(getWinners(_, K)).flatten.toSet
    winners.toList match {
      case Nil => "Neither"
      case 'B' :: Nil => "Blue"
      case 'R' :: Nil => "Red"
      case _ => "Both"
    }
  }
  
  //////////
  // main //
  //////////
  if (args.length > 0) Console.setIn(new java.io.FileInputStream(args(0)))
  if (args.length > 1) Console.setOut(new java.io.FileOutputStream(args(1)))

  for (t <- 1 to readInt) {
    val Array(n, k) = readLine.split(" ").map(_.toInt)
    val lines = (for (r <- 1 to n) yield readLine).toList
    println(s"Case #${t}: ${solve(lines, k)}")
  }
}