Solution to http://codingdojo.org/kata/Minesweeper/ - Functional Kubs

Minesweeper.scala

object Minesweeper extends App {
  /*
   * Solution to http://codingdojo.org/kata/Minesweeper/ (sort of, doesn't read from stdin)
   */
  type Row = Int
  type Col = Int

  def emptyMap= Map[(Row, Col), Int]().withDefaultValue(0)

  val rowLen = 4
  val colLen = 4

  val simpleInput =
    """
*...
....
.*..
....
""".stripMargin

  val simpleInputWithoutSpaces = simpleInput.replaceAll("\n", "")

  def findSurroundingCells(row: Row, col: Col) =
    for (x <- row - 1 to row + 1; y <- col - 1 to col + 1) yield (x,y)

  def findCell(idx: Int, col: Col): (Row, Col) = (idx / col, idx % col)

  val answer = simpleInputWithoutSpaces.zipWithIndex.foldLeft(emptyMap) {
    case (counts, ('*', idx)) =>
      val cell = findCell(idx, colLen)
      val x = findSurroundingCells(cell._1, cell._2) map { _ -> 1 }
      x.toMap ++ counts.map{ case (k,v) => k -> (v + x.toMap.getOrElse(k, 0)) }
    case (counts, (_, _)) => counts
  }

  simpleInputWithoutSpaces.zipWithIndex foreach {
    case (char, idx) =>
      (char, idx) match {
        case ('.', idx) => print(answer.getOrElse(findCell(idx, colLen), 0))
        case ('*', _) => print('*')
      }
      if (idx % colLen == colLen - 1) println()
  }
}