Advent of Code 2021-7.scala

import java.io.FileInputStream
import scala.annotation.tailrec
import scala.io.StdIn
import scala.math.abs

def minFuel(crabs: Vector[Int], fuels: (Vector[Int], Int) => Int): Int =
  (crabs.min to crabs.max).map(position => fuels(crabs, position)).min

def solve7_1(inputs: Vector[Int]): Int =
  def fuels(crabs: Vector[Int], target: Int): Int =
    crabs.map(crab => abs(crab - target)).sum

  minFuel(inputs, fuels)

def solve7_2(inputs: Vector[Int]): Int =
  def fuels(crabs: Vector[Int], target: Int): Int =
    crabs.map(crab => {
      val diff = abs(crab - target)
      diff * (1 + diff) / 2
    }).sum

  minFuel(inputs, fuels)

@main def solve7(): Unit =
  val in = new FileInputStream("example7-2.in")
  System.setIn(in)
  val inputs = StdIn.readLine().split(",").map(_.toInt).toVector
  println(solve7_1(inputs))
  println(solve7_2(inputs))