TextMessageOutrage.scala

object TextMessageOutrage extends App {

  def minNumberOfKeyPressed(numberOfKey: Int, letterFrequencies: Seq[Int]): Long = {
    for {
      (freqs, index) <- (letterFrequencies sortWith (_ > _) grouped numberOfKey).zipWithIndex
      freq <- freqs
    } yield freq.toLong * (index + 1)
  }.sum

  def process(lineIn: Iterator[String])(lineOut: String => Unit) =
    for (i <- 1 to lineIn.next().toInt) {
      def readInts() = lineIn.next() split ' ' map (_.toInt)
      val Array(p, k, l) = readInts()
      val letterFrequencies = readInts()
      lineOut(s"Case #$i: ${minNumberOfKeyPressed(k, letterFrequencies)}")
    }

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

}

TextMessageOutrageTest.scala

import org.scalatest._

import TextMessageOutrage._

class TextMessageOutrageTest extends FunSuite {

  test("sample #1") {
    assert(minNumberOfKeyPressed(2, Seq(8, 2, 5, 2, 4, 9)) === 47)
  }
  test("sample #2") {
    assert(minNumberOfKeyPressed(9, Seq(1, 1, 1, 100, 100, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 10, 11, 11, 11, 11, 1, 1, 1, 100)) === 397)
  }

  test("sample case") {
    val input = """2
3 2 6
8 2 5 2 4 9
3 9 26
1 1 1 100 100 1 1 1 1 1 1 1 1 1 1 1 1 10 11 11 11 11 1 1 1 100""".lines

    val expected = """Case #1: 47
Case #2: 397""".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.out.ref").getLines()

    lineComparison(input, expected)
  }

  test("full large case") {
    val input = io.Source.fromFile("A-large-practice.in").getLines()
    val expected = io.Source.fromFile("a.large.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.")
  }

}