Day 6

core/src/main/scala/tf/bug/aoc/Day.scala

@@ -4,6 +4,7 @@ import cats._
 import cats.effect._
 import fs2._
 
-trait Day:
+trait Day {
   def part1[F[_]: Async]: Pipe[F, String, String]
   def part2[F[_]: Async]: Pipe[F, String, String]
+}

core/src/main/scala/tf/bug/aoc/Main.scala

@@ -7,13 +7,13 @@ import cats.syntax.all._
 import java.nio.charset.StandardCharsets
 import fs2._
 
-object Main extends IOApp:
+object Main extends IOApp {
 
   def years: Map[Int, Year] = Map(
     2020 -> y2020.y2020,
   )
 
-  override def run(args: List[String]): IO[ExitCode] =
+  override def run(args: List[String]): IO[ExitCode] = {
     val year: IO[Year] = selectYear[IO]
     val day: IO[Day] = year >>= selectDay[IO]
     val part: IO[Pipe[IO, String, String]] = day >>= selectPart[IO]
@@ -24,8 +24,9 @@ object Main extends IOApp:
         .through(io.stdoutLines(StandardCharsets.UTF_8))
         .compile.drain
     }.as(ExitCode.Success)
+  }
 
-  def selectYear[F[_]: Monad: Console]: F[Year] =
+  def selectYear[F[_]: Monad: Console]: F[Year] = {
     val ask = Console[F].print("Select year: ")
     val receive = Console[F].readLine
     val year: F[Option[Year]] = (ask >> receive).map(_.toIntOption >>= years.get)
@@ -33,8 +34,9 @@ object Main extends IOApp:
       case Some(year) => year.pure[F]
       case None => selectYear[F]
     }
+  }
   
-  def selectDay[F[_]: Monad: Console](year: Year): F[Day] =
+  def selectDay[F[_]: Monad: Console](year: Year): F[Day] = {
     val ask = Console[F].print("Select day: ")
     val receive = Console[F].readLine
     val day: F[Option[Day]] = (ask >> receive).map(_.toIntOption >>= year.days.get)
@@ -42,8 +44,9 @@ object Main extends IOApp:
       case Some(day) => day.pure[F]
       case None => selectDay[F](year)
     }
+  }
 
-  def selectPart[F[_]: Async: Console](day: Day): F[Pipe[F, String, String]] =
+  def selectPart[F[_]: Async: Console](day: Day): F[Pipe[F, String, String]] = {
     val ask = Console[F].print("Select part: ")
     val receive = Console[F].readLine
     val part: F[Option[Int]] = (ask >> receive).map(_.toIntOption)
@@ -52,3 +55,6 @@ object Main extends IOApp:
       case Some(2) => day.part2[F].pure[F]
       case _ => selectPart[F](day)
     }
+  }
+
+}

core/src/main/scala/tf/bug/aoc/Year.scala

@@ -1,4 +1,5 @@
 package tf.bug.aoc
 
-trait Year:
+trait Year {
   def days: Map[Int, Day]
+}

core/src/main/scala/tf/bug/aoc/y2020/Day1.scala

@@ -8,7 +8,7 @@ import java.nio.charset.StandardCharsets
 import scala.util.Try
 import tf.bug.aoc.Day
 
-object Day1 extends Day:
+object Day1 extends Day {
 
   override def part1[F[_]: Async]: Pipe[F, String, String] =
     parts[F](2)
@@ -29,3 +29,5 @@ object Day1 extends Day:
     ints.combinations(num).collectFirst {
       case v if v.sum == target => v.product
     }
+
+}

core/src/main/scala/tf/bug/aoc/y2020/Day2.scala

@@ -6,7 +6,7 @@ import cats.syntax.all._
 import fs2._
 import tf.bug.aoc.Day
 
-object Day2 extends Day:
+object Day2 extends Day {
 
   case class Policy(min: Int, max: Int, letter: Char)
   case class Entry(policy: Policy, password: String)
@@ -45,3 +45,5 @@ object Day2 extends Day:
         .foldMap(ent => if(validation(ent)) 1 else 0)
         .map(_.show)
     }
+
+}

core/src/main/scala/tf/bug/aoc/y2020/Day3.scala

@@ -5,7 +5,7 @@ import cats.syntax.all._
 import fs2._
 import tf.bug.aoc.Day
 
-object Day3 extends Day:
+object Day3 extends Day {
 
   case class Path(x: Int, treeCount: Long)
 
@@ -44,3 +44,5 @@ object Day3 extends Day:
           }
       }.map(_.treeCount)
     }
+
+}

core/src/main/scala/tf/bug/aoc/y2020/Day4.scala

@@ -6,7 +6,7 @@ import cats.syntax.all._
 import fs2._
 import tf.bug.aoc.Day
 
-object Day4 extends Day:
+object Day4 extends Day {
 
   val whitespace: Parser1[Unit] = P.charIn(" ").void
 
@@ -17,7 +17,7 @@ object Day4 extends Day:
 
   val parseMap: P[Map[String, String]] = (P.repSep(parseEntry, min = 0, sep = whitespace) <* P.until(P.end)).map(_.toMap)
 
-  override def part1[F[_]: Async]: Pipe[F, String, String] =
+  override def part1[F[_]: Async]: Pipe[F, String, String] = {
     val requiredKeys = Set(
       "byr", "iyr", "eyr", "hgt", "hcl", "ecl", "pid"
     )
@@ -25,8 +25,9 @@ object Day4 extends Day:
       val keySet = m.keySet
       requiredKeys.forall(keySet.contains)
     }
+  }
 
-  override def part2[F[_]: Async]: Pipe[F, String, String] =
+  override def part2[F[_]: Async]: Pipe[F, String, String] = {
     val hexChar: P[Unit] = P.charIn(('0' to '9') ++ ('a' to 'f')).void
     val validateColor: P[Unit] = P.char('#') *> hexChar.replicateA(6).void
     val eyeColors: Set[String] = Set(
@@ -56,6 +57,7 @@ object Day4 extends Day:
       lazy val validPid = m.get("pid").fold(false)(validatePid.parseAll(_).isRight)
       validByr && validIyr && validEyr && validHgt && validHcl && validEcl && validPid
     }
+  }
 
   def parts[F[_]: Async](validator: Map[String, String] => Boolean): Pipe[F, String, String] =
     (lines: Stream[F, String]) => {
@@ -70,3 +72,5 @@ object Day4 extends Day:
         .foldMap(if(_) 1 else 0)
         .map(_.show)
     }
+
+}

core/src/main/scala/tf/bug/aoc/y2020/Day5.scala

@@ -6,7 +6,7 @@ import fs2._
 import scala.collection.SortedSet
 import tf.bug.aoc.Day
 
-object Day5 extends Day:
+object Day5 extends Day {
 
   override def part1[F[_]: Async]: Pipe[F, String, String] =
     (lines: Stream[F, String]) => {
@@ -44,3 +44,5 @@ object Day5 extends Day:
         val newBit = ((ch & 4) >>> 2) ^ 1
         (id * 2) + newBit
     })
+
+}

core/src/main/scala/tf/bug/aoc/y2020/Day6.scala

@@ -0,0 +1,27 @@
+package tf.bug.aoc.y2020
+
+import cats.effect._
+import cats.syntax.all._
+import fs2._
+import tf.bug.aoc.Day
+
+object Day6 extends Day {
+
+  override def part1[F[_]: Async]: Pipe[F, String, String] =
+    parts(_ | _)
+
+  override def part2[F[_]: Async]: Pipe[F, String, String] =
+    parts(_ & _)
+
+  def parts[F[_]: Async](reduction: (Set[Char], Set[Char]) => Set[Char]): Pipe[F, String, String] =
+    (lines: Stream[F, String]) => {
+      lines.groupAdjacentBy(_.nonEmpty).collect {
+        case (true, strings) =>
+          strings
+            .map(_.toSet)
+            .reduceLeftOption(reduction)
+            .getOrElse(Set.empty[Char])
+      }.map(_.size).foldMonoid.map(_.show)
+    }
+
+}

core/src/main/scala/tf/bug/aoc/y2020/y2020.scala

@@ -2,11 +2,15 @@ package tf.bug.aoc.y2020
 
 import tf.bug.aoc.{Day, Year}
 
-object y2020 extends Year:
+object y2020 extends Year {
+
   override def days: Map[Int, Day] = Map(
     1 -> Day1,
     2 -> Day2,
     3 -> Day3,
     4 -> Day4,
     5 -> Day5,
+    6 -> Day6,
   )
+
+}