-scala: Stepic algorithms

PointCover.scala

/**
  * @author Alexander Krasniansky
  */
object PointCover extends App {

  case class Point(x: Int)
  case class Segment(start: Int, end: Int)

  def cover(points: Seq[Point], segmentLength: Int): Seq[Segment] = points match {
    case x :: _ =>
      def min(points: Seq[Point]) = points sortWith { _.x < _.x } head

      val mp       = min(points)
      val seg      = Segment(mp.x, mp.x + segmentLength)
      val filtered = points filter { _.x > seg.end }

      seg +: cover(filtered, segmentLength)
    case _ => Nil
  }

}

Naive Scala implementation of https://stepic.org/lesson/%D0%92%D0%B2%D0%B5%D0%B4%D0%B5%D0%BD%D0%B8%D0%B5-13238/step/2?course=%D0%90%D0%BB%D0%B3%D0%BE%D1%80%D0%B8%D1%82%D0%BC%D1%8B-%D1%82%D0%B5%D0%BE%D1%80%D0%B8%D1%8F-%D0%B8-%D0%BF%D1%80%D0%B0%D0%BA%D1%82%D0%B8%D0%BA%D0%B0-%D0%9C%D0%B5%D1%82%D0%BE%D0%B4%D1%8B&unit=3424

Tests

val points: Seq[Point] = Seq(
  Point(6),  Point(8),  Point(12), 
  Point(13), Point(17), Point(18),
  Point(22), Point(25)
)

assert(cover(points, 6).size == 3)
assert {
  cover(points, 6).contains(Segment(6, 12))  &&
  cover(points, 6).contains(Segment(13, 19)) &&
  cover(points, 6).contains(Segment(22, 28))
}