RopeIntranet.scala

object RopeIntranet extends App {

  def isCrossed(x: Array[Int], y: Array[Int]): Boolean = (x(0) - y(0)) * (x(1) - y(1)) < 0

  def numberOfInterection(wires: IndexedSeq[Array[Int]]): Int = {
    for {
      i <- 0 until wires.size - 1
      j <- i + 1 until wires.size
    } yield isCrossed(wires(i), wires(j))
  }.count(_ == true)

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

  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()
  }

}

RopeIntranetTest.scala

import org.scalatest._

import RopeIntranet._

class RopeIntranetTest extends FunSuite {
  
  test("isCrossed") {
    assert(isCrossed(Array(1, 10), Array(5,5)) === true)
    assert(isCrossed(Array(7, 7), Array(5,5)) === false)
  }
  
  test("sample #1") {
    assert(numberOfInterection(Vector(Array(1,10), Array(5,5), Array(7,7))) === 2)
  }
  
  test("sample #2") {
    assert(numberOfInterection(Vector(Array(1,1), Array(2,2))) === 0)
  }
  
  test("sample case") {
    val input = """2
3
1 10
5 5
7 7
2
1 1
2 2""".lines

    val expected = """Case #1: 2
Case #2: 0""".lines

    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)
  }

  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)
  }

  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)
  }
}