MushroomMonster.scala

import java.io.FileOutputStream

import scala.io.Source

object MushroomMonster {
  val INPUT = "A-large-practice.in"
  val OUTPUT = INPUT.takeWhile(_ != '.') + ".out"

  def main(args: Array[String]): Unit = {
    val itr = Source.fromFile(INPUT).getLines()
    val sets = itr.next().toInt

    val writer = new FileOutputStream(OUTPUT)
    //    val writer = Console.out
    try {
      Console.withOut(writer) {
        for (set <- 1 to sets) {
          itr.next()
          val mushrooms = itr.next().split(' ').map(_.toInt)
          println(s"Case #$set: ${solve1(mushrooms)} ${solve2(mushrooms)}")
        }
      }
    } finally {
      writer.flush()
      writer.close()
    }
  }

  /**
   * 아무때나 막 먹는 경우의 최소 수
   */

  def solve1(mushrooms: Array[Int]): Int = {
    def _solve(m: IndexedSeq[Int], head: Int, accr: Int = 0): Int = m match {
      case _ if m.isEmpty => accr
      case x +: xs if head <= x => _solve(xs, x, accr)
      case x +: xs => _solve(xs, x, accr + head - x)
    }
    _solve(mushrooms.tail, mushrooms.head)
  }

  /**
   * 정해진 속도로 먹을 때 최소의 수.
   * @param mushrooms
   * @return
   */
  def solve2(mushrooms: Array[Int]): Int = {
    val m = mushrooms.tail.foldLeft((0, mushrooms.head)){
      case ((maxValue, head), x) => (maxValue max (head - x), x)
    }._1
    
    def _solve(mush: IndexedSeq[Int], accr: Int = 0): Int = mush match {
      case _ if mush.length == 1 => accr
      case x +: xs if m <= x => _solve(xs, accr + m)
      case x +: xs => _solve(xs, accr + x)
    }
    _solve(mushrooms)
  }
}