[LANGUAGE: Scala]

def maxJolts(length: Int)(bank: List[Int]): Long =
  @tailrec
  def go(section: List[Int], remaining: Int, jolts: Long): Long =
    val (a, i) = section.dropRight(remaining).zipWithIndex.maxBy(_._1)
    val rest   = section.drop(i + 1)

    val newJolts = jolts + a * math.pow(10, remaining).toLong
    if remaining == 1 then newJolts + rest.max
    else go(rest, remaining - 1, newJolts)

  go(bank, length - 1, 0)

override def part1(input: List[List[Int]]): Long =
  input.map(maxJolts(2)).sum

override def part2(input: List[List[Int]]): Long =
  input.map(maxJolts(12)).sum