CodeFight - Counting characters

codeCharCount.scala

def shortestSolutionLength(source: Array[String]): Int = {
	sealed abstract class State
	case class Counting() extends State
	case class Dash() extends State
	case class SingleLineComment() extends State
	case class Astrix() extends State
	case class MultiLineComment() extends State

	var count: Int = 0

	def transition[T <: State](state: T, c: Char): State = {
		if(c == ' ') state
		else {
			state match {
				case Counting() =>
					c match {
						case '/' =>
							count = count + 1
							Dash()
						case '\n' =>
							Counting()
						case _ =>
							count = count + 1
							Counting()
					}
				case Dash() =>
					c match {
						case '/' =>
							count = count - 1
							SingleLineComment()
						case '*' =>
							count = count - 1
							MultiLineComment()
						case _ => 
							count = count + 1
							Counting()
					}
				case SingleLineComment() =>
					c match {
						case '\n' => Counting()
						case _ => SingleLineComment()
					}
				case Astrix() =>
					c match {
						case '/' => Counting()
						case _ => MultiLineComment()
					}
				case MultiLineComment() =>
					c match {
						case '*' => Astrix()
						case _ => MultiLineComment()
					}
			}
		}
	}

	source.mkString("\n").toList.foldLeft(Counting().asInstanceOf[State])(transition)
	count
}