Interview exercise. Find the longest subsequence in an array

FindLIS.scala

object FindLIS {

  def findLIS(initialArray: Array[Int]): Int = {
    if (initialArray.length < 2) return initialArray.length

    val allSubSequences = initialArray.zipWithIndex.foldLeft(List.empty[Array[Int]]) {
      case (currentSubSequences, (nextValue, index)) =>
        currentSubSequences ::: getSubsequenceFromArray(Array(nextValue), initialArray.drop(index))
    }

    allSubSequences.maxBy(_.length).length
  }

  private def getSubsequenceFromArray(accumulator: Array[Int], remainder: Array[Int]): List[Array[Int]] = {
    if (remainder.isEmpty) return List(accumulator)

    val nextElement = remainder.head
    if (nextElement > accumulator.last)
      getSubsequenceFromArray(accumulator :+ nextElement, remainder.tail) ::: getSubsequenceFromArray(
        accumulator,
        remainder.tail
      )
    else
      getSubsequenceFromArray(accumulator, remainder.tail)
  }
}