93 lines
2.5 KiB
Scala
93 lines
2.5 KiB
Scala
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package aoc.day7
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import aoc._
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val possibleCards = "AKQJT98765432".reverse
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enum DeckKind:
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case High
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case Pair
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case Pairs
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case Three
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case House
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case Four
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case Five
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object DeckKind:
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def apply(deck: String) =
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val ranks = deck.sorted.toArray
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if ranks(0) == ranks(4) then Five
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else if ranks(0) == ranks(3) || ranks(1) == ranks(4) then Four
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else if ranks(0) == ranks(2) && ranks(3) == ranks(4) || ranks(0) == ranks(
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1
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) && ranks(2) == ranks(4)
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then House
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else if ranks(0) == ranks(1) && ranks(2) == ranks(3) || ranks(0) == ranks(
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1
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) && ranks(3) == ranks(4) || ranks(1) == ranks(2) && ranks(3) == ranks(4)
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then Pairs
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else
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lazy val three = (0 until ranks.length - 2)
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.find(i => ranks(i) == ranks(i + 2))
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.map(i => Three)
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lazy val pair = (0 until ranks.length - 1)
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.find(i => ranks(i) == ranks(i + 1))
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.map(i => Pair)
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three.orElse(pair).getOrElse(High)
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import DeckKind._
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case class Hand(deck: String, bet: Int):
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def deckRank(using cardToRank: Map[Char, Int]) = deck.map(cardToRank(_))
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val kind = DeckKind(deck)
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lazy val bestKind =
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deck.iterator
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.foldLeft(Iterator("")) { (it, chr) =>
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if chr == 'J' then it.flatMap(s => possibleCards.map(s + _))
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else it.map(_ + chr)
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}
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.map(DeckKind(_))
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.maxBy(_.ordinal)
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inline def nonZero(ins: Int*) = ins.find(_ != 0).getOrElse(0)
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object Parser extends CommonParser:
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val deck = (s"[${possibleCards}]{5}").r
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val hand = deck ~ num ^^ { case (deck ~ num) => Hand(deck, num) }
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def apply(s: String) =
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parse(hand, s).get
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// part 1
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def handOrdering(toKind: Hand => DeckKind)(using cardOrdering: Map[Char, Int]) =
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new Ordering[Hand]:
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override def compare(dx: Hand, dy: Hand): Int =
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val (x, y) = (toKind(dx), toKind(dy))
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if x.ordinal != y.ordinal then x.ordinal.compareTo(y.ordinal)
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else nonZero(dx.deckRank.zip(dy.deckRank).map(_ compareTo _)*)
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def print(using Ordering[Hand]) =
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val hands = lines.map(Parser(_)).toSeq
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val res =
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hands.sorted.zipWithIndex
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.map((h, idx) => h.bet * (idx + 1L))
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.sum
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println(res)
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def part1 =
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val ordering = possibleCards.zipWithIndex.toMap
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val handOrd = handOrdering(_.kind)(using ordering)
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print(using handOrd)
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// part 2
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def part2 =
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val ordering = "J23456789TQKA".zipWithIndex.toMap
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val handOrd = handOrdering(_.bestKind)(using ordering)
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print(using handOrd)
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@main def Day7(part: Int) = part match
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case 1 => part1
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case 2 => part2
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