Inverse Fizzbuzz by k.ONO (shout_poor)

gistfile1.scala

/** 
 * Inverse Fizzbuzz 
 * http://www.jasq.org/2/post/2012/05/inverse-fizzbuzz.html 
 **/
object InverseFizzBuzz extends App {

  val fizzbuzz = new PartialFunction[Int, (Int, String)] {
    def apply(x:Int) = (x, (x%3,x%5) match {
      case (0, 0) => "fizzbuzz"
      case (0, _) => "fizz"
      case (_, 0) => "buzz"
      case _      => ""
    })
    def isDefinedAt(x:Int) = (x%3==0 || x%5==0)
  }

  def invFizzBuzz(pattern:Seq[String], searchRange: Seq[Int]) = {

    val (f, e) = searchRange.filter(fizzbuzz.isDefinedAt)
      .map((x) => Stream.from(x).collect(fizzbuzz))
      .map(pattern.zip(_).map(x => (x._2._1, x._1, x._2._2)))
      .filter(l => l.foldLeft(true) ((z, x) => z && x._2 == x._3))
      .map(l => (l.head._1, l.last._1))
      .minBy(x => x._2 - x._1)
    
    f to e
  }

  def _p(s:Seq[String]) = {
    val rng = 1 to 15
    println("pattern : %s" format(s.map(s => s.mkString("'", "", "'"))))
    println(invFizzBuzz(s, rng))
    println("")
  }
  _p(Seq("fizz"))
  _p(Seq("buzz"))
  _p(Seq("fizz","buzz"))
  _p(Seq("buzz","fizz"))
  _p(Seq("fizz","buzz","fizz"))
  _p(Seq("fizz","fizz"))
  _p(Seq("fizz","fizz","buzz"))
}