RosettaCodeData/Task/Combinations/Scala/combinations-1.scala

9 lines
320 B
Scala

implicit def toComb(m: Int) = new AnyRef {
def comb(n: Int) = recurse(m, List.range(0, n))
private def recurse(m: Int, l: List[Int]): List[List[Int]] = (m, l) match {
case (0, _) => List(Nil)
case (_, Nil) => Nil
case _ => (recurse(m - 1, l.tail) map (l.head :: _)) ::: recurse(m, l.tail)
}
}