Factorion

factorion.scala

object factorion extends App {

	lazy val N: Stream[Int] = Stream.cons(1, N.map(_ + 1))
	lazy val fact: Stream[Int] = Stream.cons(1, fact.zip(N).map(a => a._1 * a._2))

	val factmap =  0 to 9 map { a => a.toString -> fact(a) } toMap

	def esFactorion(n: Int) = (n.toString.toList map (c => factmap.get(c.toString).get) sum) == n

	val start = System.nanoTime

	val factoriones = 1 to 2500000 filter ( esFactorion ) mkString(",")
	println("Factoriones: " + factoriones)

	val elapsed_ms = (System.nanoTime - start ) / 1000000
                                                  //> elapsed_ms  : Long = 1769
	println("Elapsed time: " + elapsed_ms + "ms")

}