GCube.scala

object GCube extends App {
  class Cuboid(a: Int*) {
    def query(l: Int, r: Int): Double =
      math.exp(a.toSeq.slice(l, r + 1).map(math.log(_)).sum / (r - l + 1))
  }

  def process(lineIn: Iterator[String])(lineOut: String => Unit) =
    for (i <- 1 to lineIn.next().toInt) {
      def readInts() = lineIn.next().split(' ').map(_.toInt)
      val Array(n, m) = readInts()
      val cuboid = new Cuboid(readInts():_*)
      lineOut(s"Case #$i:")
      for (j <- 1 to m) {
        val Array(l, r) = readInts()
        lineOut(f"${cuboid.query(l, r)}%1.9f")
      }
    }

  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()
  }
}

GCubeTest.scala

import org.scalatest._

import GCube._

class GCubeTest extends FunSuite with Matchers {

  test("sample #1") {
    val cuboid = new Cuboid(1,4)
    cuboid.query(0, 0) should equal (1.000000000 +- 1e-6)
    cuboid.query(0, 1) should equal (2.000000000 +- 1e-6)
  }

  test("sample #2") {
    val cuboid = new Cuboid(1, 2, 3)
    cuboid.query(0, 1) should equal (1.414213562 +- 1e-6)
    cuboid.query(1, 2) should equal (2.449489743 +- 1e-6)
  }

  test("sample case") {
    val input = """2
2 2
1 4
0 0
0 1
3 2
1 2 3
0 1
1 2""".lines

    val expected = """Case #1:
1.000000000
2.000000000
Case #2:
1.414213562
2.449489743""".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)
  }

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

}