GFiles.scala

object GFiles extends App {

  def numberOfFiles(status: Seq[(Int, Long)]): Option[Long] = {
    val (froms, tos) = status.map {
      case (p, k) =>
        (if (p < 100) 100 * k / (p + 1) else k - 1, if (p > 0) 100 * k / p else Long.MaxValue)
    }.unzip
    if (tos.min - 1 == froms.max) Some(tos.min) else None
  }

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

  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()
  }
}

GFilesTest.scala

import org.scalatest._

import GFiles._

class GFilesTest extends FunSuite with Matchers {

  test("sample #1") {
    assert(numberOfFiles(Seq((20, 1), (100, 5))) === Some(5))
  }

  /*
   0 0
8 2
8 2
17 4
30 7
39 9
69 16
73 17
82 19
91 21
   */
  test("sample #2") {
    assert(numberOfFiles(Seq((0, 0), (8, 2), (8,2), (17,4),
      (30,7), (39, 9), (69, 16), (73, 17), (82, 19), (91, 21))) === Some(23))
  }

  test("sample case") {
    val input = """3
2
20 1
100 5
10
25 241
27 262
43 407
44 413
57 536
64 601
67 637
84 789
95 893
96 903
10
0 0
8 2
8 2
17 4
30 7
39 9
69 16
73 17
82 19
91 21""".lines

    val expected = """Case #1: 5
Case #2: -1
Case #3: 23""".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.")
  }

}