package aoc
package day02

val dayNumber = "02"

@main def part1: Unit =
  println(part1(loadInput(dayNumber)))

@main def part2: Unit =
  println(part2(loadInput(dayNumber)))

def part1(input: String): String =

  def isSafe(rs: Array[Int]): Boolean =
    val rsInc = if rs.head > rs.last then rs.reverse else rs
    rsInc
      .sliding(2)
      .map { case Array(a, b) => b - a }
      .forall(diff => diff >= 1 && diff <= 3)

  input
    .split("\n")
    .map(_.split(" ").map(_.toInt))
    .count(isSafe)
    .toString

def part2(input: String): String =

  def isSafe(rs: Array[Int]): Boolean =
    val rsInc = if rs.head > rs.last then rs.reverse else rs
    rsInc
      .sliding(2)
      .map { case Array(a, b) => b - a }
      .forall(diff => diff >= 1 && diff <= 3)

  def isSafeWithTolerance(rs: Array[Int]): Boolean =
    isSafe(rs) ||
      (for i <- 0 to rs.length
      yield isSafe(rs.take(i) ++ rs.drop(i + 1)))
        .exists(identity)

  input
    .split("\n")
    .map(_.split(" ").map(_.toInt))
    .count(isSafeWithTolerance)
    .toString