s1e04assignments.scala

object App{
  def main(args: Array[String]): Unit ={
    val lists = List(
      Nil,
      List(),

      List(1),
      List(1,2),
      List(1,2,3),

      List(1,1),
      List(1,1,1),

      List(1, 2, 2, 3, 4, 5, 6, 6, 6, 6, 7, 7, 8, 8, 8, 8, 8, 9, 0),

      List("a", "a", "a", "b", "c", "c", "c")
    )

    for(list <- lists){
      val deduped = dedup(list)
      val reversed = reverse(list)
      println(s"orig: $list, reversed: $reversed, deduped: $deduped")
      println ("\n\n")
    }


  }

  def reverse[A](list: List[A]): List[A] = {
    list match  {
      case first :: rest => reverse(rest) :+ first
      //case first :: rest => reverse(rest) ::: List(first)
      //case first :: rest => reverse(rest) ++ List(first)
      case Nil => Nil
    }
  }

  def dedup[A](list: List[A]): List[A] = {

    list match {
      case first :: second :: rest if first == second => dedup(second :: rest)
      case first :: rest => first :: dedup(rest)
      case Nil => Nil
    }
  }
}