Consonants.scala

object Consonants extends App {

  def nValue(s: String, n: Int): Long = ((0, 0, 0L) /: (0 until s.size)) {
    case ((lastCount, last, acc), i) =>
      val count = if ("aeiou" contains s(i)) 0 else lastCount + 1
      val (nextLast, nextAcc) =
        if (count >= n) (i - n + 2, acc + (i - n - last + 2) * (s.size - i)) else (last, acc)
      (count, nextLast, nextAcc)
  }._3

  def process(lineIn: Iterator[String])(lineOut: String => Unit) =
    for (i <- 1 to lineIn.next().toInt) {
      val Array(s, n) = lineIn.next() split ' '
      lineOut(s"Case #$i: ${nValue(s, n.toInt)}")
    }

  val filename = "A-large-practice"
  val writer = new java.io.PrintWriter(filename + ".out")
  try {
    process(io.Source.fromFile(filename + ".in").getLines) { s =>
      writer.println(s); writer.flush()
    }
  } finally {
    writer.flush(); writer.close()
  }

}

ConsonantsTest.scala

import org.scalatest._

import Consonants._

class ConsonantsTest extends FunSuite {

  test("sample #1") {
    assert(nValue("quartz", 3) === 4)
  }

  test("sample #2") {
    assert(nValue("straight", 3) === 11)
  }

  test("sample #3") {
    assert(nValue("gcj", 2) === 3)
  }

  test("sample #4") {
    assert(nValue("tsetse", 2) === 11)
  }

  test("sample case") {
    val input = """4
quartz 3
straight 3
gcj 2
tsetse 2""".lines

    val expected = """Case #1: 4
Case #2: 11
Case #3: 3
Case #4: 11""".lines

    lineComparison(input, expected)
  }

  test("full small case") {
    val input = io.Source.fromFile("A-small-practice.in").getLines()
    val expected = io.Source.fromFile("A-small-practice.out.ref").getLines()

    lineComparison(input, expected)
  }

  ignore("full large case") {
    val input = io.Source.fromFile("A-large-practice.in").getLines()
    val expected = io.Source.fromFile("A-large-practice.out.ref").getLines()

    lineComparison(input, expected)
  }

  def lineComparison(input: Iterator[String], expected: Iterator[String]) {
    process(input) { s =>
      for (line <- s.lines) assert(line.trim === expected.next().trim)
    }
    assert(expected.hasNext === false, "Finished too fast.")
  }

}