P10 (*) Run-length encoding of a list. Use the result of problem P09 to implement the so-called run-length encoding data compression method. Consecutive duplicates of elements are encoded as tuples (N, E) where N is the number of duplicates of the element E. Example: scala> encode(List('a, 'a, 'a, 'a, 'b, 'c, 'c, 'a, 'a, 'd, 'e, 'e, 'e, 'e)) res…

encode.scala

def encode[A](input: List[A]): List[(Int, A)] = input match {
  case Nil => Nil
  case h :: t => (pack(input)).map(shorten)
}

def shorten[A](input: List[A]): List[(Int, A)] = input match {
  case Nil => Nil
  case h :: t => (input.length, h)
}