Day4.scala

package sungkmi.aoc2020.day4

import scala.collection.JavaConverters._
import scala.util.Try

def parsePassport(lines: String): Map[String, String] =
  lines.lines.iterator.asScala.flatMap(_ `split` " ").map{ (field: String) =>
    val Array(k, v) = field `split` ":"
    (k, v)
  }.toMap

def isValid(map: Map[String, String]): Boolean =
  val keys = Seq("byr", "iyr", "eyr", "hgt", "hcl", "ecl", "pid")
  keys.forall(map.keySet.contains)
  
@main def part1: Unit =
  val ans = passports.count(isValid)
  println(ans)

def range(atLeast: Int, atMost: Int): String => Boolean = (v: String) =>
  Try(v.toInt).toEither match
    case Right(n) if atLeast <= n && n <= atMost => true
    case _ => false

def regex(r: String): String => Boolean = _.matches(r)

val validations: Map[String, String => Boolean] = Map(
  "byr" -> range(1920, 2002),
  "iyr" -> range(2010, 2020),
  "eyr" -> range(2020, 2030),
  "hgt" -> {(s: String) =>
    val (n, unit) = s.splitAt(s.size - 2)
    unit match
      case "cm" => range(150, 193)(n)
      case "in" => range(59, 76)(n)
      case _ => false
  },
  "hcl" -> regex("#([0-9]|[a-f]){6}"),
  "ecl" -> regex("amb|blu|brn|gry|grn|hzl|oth"),
  "pid" -> regex("[0-9]{9}"),
)
@main def part2: Unit =
  val ans = passports.count{ (passport: Map[String, String]) =>
    validations.forall{ (key, rule) =>
      println((key, passport.get(key).map(rule)))
      passport.get(key).map(rule).getOrElse(false)
    }
  }
  println(ans)

lazy val passportStrings: Array[String] = input.split("\n\n")

lazy val passports = passportStrings `map` parsePassport

//lazy val input = """pid:827837505 byr:1976 ...

Day4Test.scala

package sungkmi.aoc2020.day4

class Day4Test extends munit.FunSuite {

  test("parse passport") {
    val s = """ecl:gry pid:860033327 eyr:2020 hcl:#fffffd
byr:1937 iyr:2017 cid:147 hgt:183cm"""
    val expected = Map(
      "ecl" -> "gry",
      "pid" -> "860033327",
      "eyr" -> "2020",
      "hcl" -> "#fffffd",
      "byr" -> "1937",
      "iyr" -> "2017",
      "cid" -> "147",
      "hgt" -> "183cm",
    )
    assertEquals(parsePassport(s), expected)

  }
}