Inverse FizzBuzz - see http://www.jasq.org/2/post/2012/05/inverse-fizzbuzz.html

ZzubZzif.scala

object ZzubZzif {
  val fizzbuzz: PartialFunction[Int, String] = {
    case x if x % 15 == 0 => "fizzbuzz"
    case x if x % 5 == 0 => "buzz"
    case x if x % 3 == 0 => "fizz"
  }

  // I'm actually embarrassed that this is the best I can do
  def zzubzzif(seq: Seq[String]): Seq[Int] = {
    val fizzbuzzIndexed = new PartialFunction[(Int, Int), (String, Int)] {
      def isDefinedAt(v: (Int, Int)) = fizzbuzz.isDefinedAt(v._1)
      def apply(v: (Int, Int)) = (fizzbuzz(v._1), v._2)
    }

    val candidates = for {
      start <- 1 to 15
      candidateSeq = Iterator.from(start).zipWithIndex.collect(fizzbuzzIndexed).take(seq.length).toList
      if candidateSeq.map(_._1) == seq
    } yield (start, candidateSeq.last._2)

    if (candidates.isEmpty) {
      Nil
    } else {
      val range = candidates.minBy(_._2)
      range._1 to (range._1 + range._2)
    }
  }
}