distinct iterator

distinctIterator.scala

def distinctFromIterator[T](input: Iterator[T]): Iterator[T] = new Iterator[T] {
  private val seen: mutable.Set[T] = mutable.Set[T]()
  private def findNextItem(): Option[T] = {
    if(input.hasNext) {
      val n = input.next()
      val newItem = seen.add(n)
      if(newItem)
        Some(n)
      else
        findNextItem()
    } else {
      None
    }
  }