InfiniteHouseOfPancakes.scala

object InfiniteHouseOfPancakes extends App {

  def findMin(plates: Seq[Int]): Int =
    (for (max <- 1 to plates.max) yield {
      for (plate <- plates) yield (plate-1)/ max
    }.sum + max).min

  def process(lineIn: Iterator[String])(lineOut: String => Unit) =
    for (i <- 1 to lineIn.next().toInt) {
      val d = lineIn.next().toInt
      val plates = lineIn.next().split(' ').map(_.toInt)
      lineOut(s"Case #$i: ${findMin(plates)}")
    }

  val filename = "B-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()
  }

}

InfiniteHouseOfPancakesTest.scala

import org.scalatest._

import InfiniteHouseOfPancakes._

class InfiniteHouseOfPancakesTest extends FunSuite {

  test("sample #1") {
    assert(findMin(Seq(3)) === 3)
  }
  
  test("sample #2") {
    assert(findMin(Seq(1,2,1,2)) === 2)
  }
  
  test("sample #3") {
    assert(findMin(Seq(4)) === 3)
  }
  
  test("sample case") {
    val input = """3
1
3
4
1 2 1 2
1
4""".lines

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

    lineComparison(input, expected)
  }

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

    lineComparison(input, expected)
  }

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

}