def groupFreq[A,B](xs: Iterator[A], f: A => B): HashMap[B, Int] = {
    var freqMap = new HashMap[B, Int]
    for (x <- xs) freqMap = freqMap + (f(x)->(freqMap.getOrElse(f(x),0)+1))
    freqMap
  }

def sizeFreq(file: String): HashMap[Int, Int] = {
    def f(x: String) = x.length
    groupFreq[String,Int](Lines.iterator(file),f)
  }

//helper
object Lines {

  def iterator(file: String) : Iterator[String] = {
    val f = new File(file)
    scala.io.Source.fromFile(f).getLines()
  }

  def list(file: String) : List[String] = {
    val buf   = scala.io.Source.fromFile(new File(file))
    val lines = buf.getLines().toList
    buf.close()
    lines
  }

}