isSorted

isSorted

                                                                                                  
case object P {
  def isSorted[A](as: Array[A], ordered:(A,A) => Boolean): Boolean = {
     as match {
       case _ if as.isEmpty => true
       case _ => as.tail.foldLeft((true, as.head)) {
         case (t, i) => if (ordered(t._2, i)) (true, i) else (false, i)
       }._1
    }
  }
                                                                                                  
  def isSorted2[A](as: Array[A], ordered:(A,A) => Boolean): Boolean = isSortedSeq(as, ordered)
                                                                                                  
  def isSortedSeq[A](lst: Seq[A], ordered:(A,A) => Boolean): Boolean = {
    lst match {
      case Seq() => true
      case a +: Seq() => true
      case a +: as => ordered(a, as.head) && isSortedSeq(as, ordered)
    }
  }
}