ProblemA.scala

package frl.driesprong

import scala.io.Source


// https://code.google.com/codejam/contest/3264486/dashboard#s=p0
object ProblemA extends App {

  case class ProblemCase(pancakes: List[Boolean], K: Int)

  val lines = Source.fromFile("/Users/fokkodriesprong/Downloads/A-small-attempt0.in").getLines().toList

  def parseLine(parts: Array[String]): ProblemCase = {
    val pancakes = parts(0).map(char => if (char == '+') true else false).toList
    ProblemCase(pancakes, parts(1).toInt)
  }

  // Get rid of the number of tests
  val cases = lines.tail.map(_.split(' ')).map(parseLine)

  def solve(pancakes: List[Boolean], K: Int = 3, flips: Int = 0): Option[Int] = {
    // If it is a minus, flip it!
    if (pancakes.length < K) {
      // Check if all remaining bools are true
      if (pancakes.forall(bool => bool)) {
        Some(flips)
      } else {
        None
      }
    } else {
      if (!pancakes.head) {
        val newPancakes = pancakes.take(K).map(!_) ++ pancakes.drop(K)
        solve(newPancakes.tail, K, flips + 1)
      }
      else {
        solve(pancakes.tail, K, flips)
      }
    }
  }

  def test(problemCase: ProblemCase, expected: Option[Int]): Unit = {
    val result = solve(problemCase.pancakes, problemCase.K)
    println(s"Case result $result")
    assert(result == expected)
  }

  // ---+-++-
  test(ProblemCase(List(false, false, false, true, false, true, true, false), 3), Some(3))
  test(ProblemCase(List(true, true, true, true, true), 3), Some(0))
  test(ProblemCase(List(false, true, false, true, false), 4), None)

  val output = cases.map(problemCase => solve(problemCase.pancakes, problemCase.K)).zipWithIndex.map {
    case (output: Option[Int], idx: Int) => s"Case #${idx + 1}: ${output.getOrElse("IMPOSSIBLE")}"
  }.mkString("\n")

  import java.io._

  val pw = new PrintWriter(new File("/Users/fokkodriesprong/Desktop/problemA.txt"))
  pw.write(output)
  pw.close()
}