aps naloga 3 scala

Naloga3.scala

import java.io.{BufferedWriter, PrintWriter, FileWriter, File}
import java.util.Scanner

object Naloga3s {
  def Reader(filename: String) = {
    val sc = new Scanner(new File(filename))
    def loop(): Stream[Int] = {
      if (sc.hasNextInt){
        sc.nextInt() #:: loop
      } else
        Stream.empty[Int]
    }
    loop()
  }

  def MultiReader(prefix: String, phase: Int, N: Int, up: Boolean) = {
    def loop(last: Int, sources: Seq[Stream[Int]]): Stream[Int] = {
      val nonEmpty = sources.filterNot(_.isEmpty)
      if(nonEmpty.length==0)
        Stream.empty[Int]
      else {
        val (low,high) = nonEmpty.
          map(_.head).zipWithIndex.partition(t => up && t._1 < last || !up && t._1 > last)
        val (e,i) = (if(high.length>0) high else low).minBy(_._1)
        e #:: loop(e, nonEmpty.updated(i, nonEmpty(i).tail))
      }
    }
    loop(0, (0 until N).map(n => Reader(prefix + "-" + phase + "-" + n)))
  }

  trait Writer{
    def write(num: Int): Writer
    def moreThanOneUsed: Boolean
  }

  def Writer(prefix: String, phase: Int, N: Int, up: Boolean): Writer = {
    val tracks = (0 until N).map(n => new PrintWriter(new BufferedWriter(new FileWriter(prefix+"-"+phase+"-"+n))))
    def mkWriter(i: Int, last: Int, used: Boolean): Writer = new Writer{
      def write(num: Int) = {
        val (ni,nu) =
          if (up && num < last || !up && num > last)
            ((i + 1) % tracks.length, true)
          else (i, used)
        tracks(ni).print(num)
        tracks(ni).print(' ')
        tracks(ni).flush()
        mkWriter(ni, num, nu)
      }

      def moreThanOneUsed = used
    }

    mkWriter(0, if (up) Integer.MIN_VALUE else Integer.MAX_VALUE, used=false)
  }

  def main(args: Array[String]){
    val inName = args(0)
    val prefix = args(1)
    val N = Integer.parseInt(args(2))
    val up = args.length <= 3 || !args(3).equalsIgnoreCase("down")

    def loop(i: Int, source: Stream[Int]){
      val sink = source.foldLeft(Writer(prefix, i, N, up))(_ write _) //looks ugly inlined
      if (sink.moreThanOneUsed) loop(i+1, MultiReader(prefix, i, N ,up))
    }
    loop(0, Reader(inName))
  }
}