permutation and combination.scala

def printList(args: TraversableOnce[_]): Unit = {
  args.foreach(print)
  println()
}  

def count(ls: List[Int]): Unit = {
		def doCount(src: List[Int], res: List[Int]): Unit = src match {
			case Nil => printList(res)
			case _ => for (element <- src) {
									doCount(src.diff(List(element)), res :+ element)
								}
		}
		doCount(ls, List());
}