toTop.scala

object Main extends App {
  def swap[A](l: List[A], topElement: A) = {
    l match {
      case l0:List[A] if l0.nonEmpty => {
          val (l1, l2 :: l3) = l0.splitAt(l0.indexOf(topElement))
          l2 :: l1 ::: l3
      }
      case _ => l
    }
  }

  val list = List("D", "Z", "CERO")
  println(swap(list, "Z"))
}