Advent of Code 2022-3.scala

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


def char2Num(c: Char): Int =
  if 'A' <= c && c <= 'Z' then
    c - 'A' + 27
  else
    c - 'a' + 1

def solve3_1(values: Vector[String]): Int =
  values.map(line => {
    val firstCompartment = line.take(line.length / 2).toSet
    val secondCompartment = line.drop(line.length / 2).toSet
    val item: Char = firstCompartment.intersect(secondCompartment).head
    char2Num(item)
  }).sum


def solve3_2(values: Vector[String]): Int =
  values.grouped(3).map(lines => {
    val badge = lines(0).toSet.intersect(lines(1).toSet).intersect(lines(2).toSet)
    char2Num(badge.head)
  }).sum

@main def solve3(): Unit =
  val in = new FileInputStream("example3-2.in")
  System.setIn(in)
  val inputs = Iterator.continually(StdIn.readLine())
    .takeWhile(line => null != line)
    .toVector
  println(solve3_1(inputs))
  println(solve3_2(inputs))