/*

Remove the Kth element from a list.
Return the list and the removed element in a Tuple. Elements are numbered from 0.
Example:
scala> removeAt(1, List('a, 'b, 'c, 'd))
res0: (List[Symbol], Symbol) = (List('a, 'c, 'd),'b)

*/

def removeAt[A](index: Int, list: List[A]): Tuple2[List[A], A] = (index, list) match {
  case (0, head :: tail) => (tail, head)
  case (_, head :: tail) => {
    val (acc, element) = removeAt(index - 1, tail)
    (head :: acc, element)
  }
}

/*

Duplicate the elements of a list a given number of times.
Example:
scala> duplicateN(3, List('a, 'b, 'c, 'c, 'd))
res0: List[Symbol] = List('a, 'a, 'a, 'b, 'b, 'b, 'c, 'c, 'c, 'c, 'c, 'c, 'd, 'd, 'd)

*/

def duplicateN[A](times: Int, list: List[A]): List[A] = list.flatMap((e: A) => List.fill(times)(e))