Fast, faster, Scala

na.scala

object Scala extends App {
  import scala.collection.mutable.ArrayBuffer
  import scala.annotation.tailrec
  val items = List("foo", 23, true)
  val before = System.currentTimeMillis()
  @tailrec def adds(n: Int, absoluteResult: ArrayBuffer[Any] = ArrayBuffer()): ArrayBuffer[Any] = {
      def foo(obj : Any) = obj match {
          case _:String => "String"
          case _:Boolean => "Boolean"
          case _:Integer => "Integer"
          case _ => throw new IllegalArgumentException()
      }

      @tailrec def add(s: List[Any]): Unit = if (s.nonEmpty) {
        absoluteResult += foo(s.head)
        add(s.tail)
      }

      if(n > 0) {
        add(items)
        adds(n - 1, absoluteResult)
      } else absoluteResult
  }

  {
    val absoluteResult = adds(1000000)
    println("Took : "+(System.currentTimeMillis() - before) + " ms, number of elements : "+absoluteResult.size)
  }
}

Wooohooo! Tried to speed up the code of Sven today. But THIS is amazing!!
Your version is nearly 56 times faster than the first version on Sven's blog and even more than 3 times faster than the optimized version posted there (measured on my machine).

• Daniel

Thanks, hope it was helpful