[haskell] Solve Day 2

answers.nix

@@ -3,4 +3,8 @@
     part1 = "53194";
     part2 = "54249";
   };
+  day2 = {
+    part1 = "2406";
+    part2 = "78375";
+  };
 }

haskell/aoc2023.cabal

@@ -15,10 +15,12 @@ common warnings
 
 library
     import:           warnings
-    build-depends:    base ^>=4.17.2.0
     hs-source-dirs:   src
     default-language: GHC2021
+    build-depends:    base ^>=4.17.2.0
+                    , containers
     exposed-modules:  Day1
+                    , Day2
 
 executable aoc2023
     import:           warnings

haskell/app/Main.hs

@@ -1,11 +1,14 @@
 {-# LANGUAGE LambdaCase #-}
+
 module Main where
 
-import qualified Day1
+import Day1 qualified
+import Day2 qualified
 import System.Environment (getArgs)
 
 main :: IO ()
 main = do
   getArgs >>= \case
     ["day1"] -> Day1.run
+    ["day2"] -> Day2.run
     args -> error $ "Invlaid args: " <> show args

haskell/default.nix

@@ -1,11 +1,11 @@
-{ mkDerivation, base, lib }:
+{ mkDerivation, base, containers, lib }:
 mkDerivation {
   pname = "aoc2023";
   version = "0.1.0.0";
   src = ./.;
   isLibrary = true;
   isExecutable = true;
-  libraryHaskellDepends = [ base ];
+  libraryHaskellDepends = [ base containers ];
   executableHaskellDepends = [ base ];
   homepage = "https://git.pub.solar/axeman/aoc2023";
   description = "Advent of Code 2023";

haskell/src/Day2.hs

@@ -0,0 +1,104 @@
+{-# LANGUAGE OverloadedRecordDot #-}
+
+module Day2 where
+
+import Control.Applicative ((<|>))
+import Data.Char (isDigit)
+import Data.Functor (($>))
+import Data.IntMap (IntMap)
+import Data.IntMap qualified as IntMap
+import Data.Maybe (fromMaybe)
+import Text.ParserCombinators.ReadP
+
+run :: IO ()
+run = do
+  games <- readInput
+  putStrLn $ "Part 1 Answer: " <> show (part1 games)
+  putStrLn $ "Part 2 Answer: " <> show (part2 games)
+
+maxRed, maxGreen, maxBlue :: Int
+maxRed = 12
+maxGreen = 13
+maxBlue = 14
+
+part1 :: Games -> Int
+part1 = sum . IntMap.keys . IntMap.filter isCompatibleGame
+
+isCompatibleGame :: [Revelation] -> Bool
+isCompatibleGame = all isCompatibleRevelation
+
+isCompatibleRevelation :: Revelation -> Bool
+isCompatibleRevelation revelation =
+  revelation.red <= maxRed
+    && revelation.green <= maxGreen
+    && revelation.blue <= maxBlue
+
+part2 :: Games -> Int
+part2 = sum . IntMap.map power
+
+power :: [Revelation] -> Int
+power rs =
+  let redPower = maximum $ map red rs
+      greenPower = maximum $ map green rs
+      bluePower = maximum $ map blue rs
+   in redPower * greenPower * bluePower
+
+type Games = IntMap [Revelation]
+
+data Revelation = Revelation {red :: Int, green :: Int, blue :: Int}
+
+fromAssocList :: [(Colour, Int)] -> Revelation
+fromAssocList m =
+  -- A fold is probably faster, but its a list of max 3 elements
+  Revelation
+    { red = fromMaybe 0 $ lookup Red m,
+      green = fromMaybe 0 $ lookup Green m,
+      blue = fromMaybe 0 $ lookup Blue m
+    }
+
+data Colour = Red | Green | Blue
+  deriving (Eq, Ord, Show)
+
+readInput :: IO Games
+readInput = do
+  inputStr <- getContents
+  case readP_to_S (parseGames <* eof) inputStr of
+    [] -> error "Parser failed"
+    ((g, _) : _) -> pure g
+
+parseGameId :: ReadP Int
+parseGameId = do
+  _ <- string "Game "
+  gameId <- read <$> many1 (satisfy isDigit)
+  _ <- string ": "
+  pure gameId
+
+parseColour :: ReadP Colour
+parseColour =
+  do
+    string "red" $> Red
+    <|> (string "green" $> Green)
+    <|> (string "blue" $> Blue)
+
+parseColourRevelation :: ReadP (Colour, Int)
+parseColourRevelation = do
+  n <- read <$> many1 (satisfy isDigit)
+  _ <- skipSpaces
+  colour <- parseColour
+  pure (colour, n)
+
+parseRevelation :: ReadP Revelation
+parseRevelation = do
+  fromAssocList <$> sepBy1 parseColourRevelation (string ", ")
+
+-- >>> readP_to_S (parseGame <* eof) "Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green"
+-- [((1,[fromList [(Red,4),(Blue,3)],fromList [(Red,1),(Green,2),(Blue,6)],fromList [(Green,2)]]),"")]
+parseGame :: ReadP (Int, [Revelation])
+parseGame = do
+  gameId <- parseGameId
+  revelations <- sepBy1 parseRevelation (string "; ")
+  pure (gameId, revelations)
+
+parseGames :: ReadP Games
+parseGames =
+  IntMap.fromList <$> sepBy1 parseGame (string "\n")

input/day2

@@ -0,0 +1,100 @@
+Game 1: 2 blue, 4 green; 7 blue, 1 red, 14 green; 5 blue, 13 green, 1 red; 1 red, 7 blue, 11 green
+Game 2: 6 blue, 3 green; 4 red, 1 green, 7 blue; 2 green
+Game 3: 4 blue, 3 red; 2 blue, 4 red, 7 green; 1 blue, 6 red, 7 green; 5 green, 10 blue; 9 green, 1 blue, 6 red; 8 blue, 1 red, 12 green
+Game 4: 15 blue, 4 green, 5 red; 2 red, 2 green, 5 blue; 3 green, 13 blue; 17 blue, 1 green, 5 red
+Game 5: 11 green, 4 red, 3 blue; 8 blue, 6 green; 8 green, 2 red, 9 blue; 4 red, 16 blue; 8 blue, 10 red, 6 green; 9 blue, 3 red, 10 green
+Game 6: 4 green, 9 red, 2 blue; 7 red, 2 green, 15 blue; 13 red, 2 green, 6 blue; 5 green, 7 blue, 6 red; 19 red, 15 blue, 4 green
+Game 7: 12 blue, 5 red; 5 green, 6 blue; 5 red, 15 blue; 5 blue, 5 red, 5 green; 1 green, 11 blue, 2 red
+Game 8: 6 red, 11 green; 5 red, 2 blue, 7 green; 7 red, 6 green
+Game 9: 5 red, 1 blue, 11 green; 4 green, 1 blue; 8 green, 2 red; 1 green, 2 red, 2 blue; 3 green, 2 red
+Game 10: 7 blue, 4 red, 11 green; 13 green, 1 red, 1 blue; 7 blue, 6 green
+Game 11: 4 blue, 7 red, 2 green; 1 green, 14 red, 3 blue; 2 green, 5 red, 3 blue
+Game 12: 6 green, 6 blue, 1 red; 1 green, 3 red, 2 blue; 2 blue, 6 red, 7 green
+Game 13: 6 red, 10 green, 13 blue; 3 red, 12 green, 9 blue; 11 blue, 1 green; 4 red, 3 blue, 13 green; 12 green, 10 blue, 6 red; 13 blue, 3 green, 3 red
+Game 14: 8 green, 1 blue, 17 red; 7 green, 11 blue, 19 red; 19 red, 9 blue, 2 green; 8 green, 20 red, 12 blue; 16 red, 3 green, 11 blue
+Game 15: 3 red, 1 green, 5 blue; 9 blue, 4 green; 6 blue, 5 green, 9 red
+Game 16: 13 blue, 1 red; 2 blue, 2 green; 1 green; 10 blue, 8 red; 4 red, 3 green, 9 blue
+Game 17: 10 blue, 2 red; 3 green, 4 red; 6 blue, 1 red, 6 green; 5 green, 7 blue, 5 red
+Game 18: 3 red, 1 green; 2 red, 5 blue; 5 blue, 2 red
+Game 19: 7 green, 4 blue, 1 red; 1 green, 4 blue, 4 red; 6 blue, 8 green; 4 green, 2 blue, 1 red; 1 red, 1 blue, 2 green
+Game 20: 13 green, 1 red, 1 blue; 12 green, 1 blue; 5 green, 1 blue, 2 red; 16 green, 3 red; 2 red, 9 green
+Game 21: 8 red, 2 green, 2 blue; 5 red, 3 blue; 2 blue, 5 red, 2 green; 7 blue
+Game 22: 9 red, 12 blue, 7 green; 7 red, 13 blue, 4 green; 9 blue, 13 red, 1 green; 3 blue, 4 red, 5 green
+Game 23: 7 green, 12 red; 6 red, 7 green, 4 blue; 1 blue, 11 red, 5 green; 4 green, 2 blue, 6 red; 12 green, 6 red, 3 blue
+Game 24: 11 red, 4 blue; 9 blue, 6 green, 17 red; 8 green, 2 red; 16 blue, 6 red, 2 green
+Game 25: 7 red, 4 blue; 7 blue, 4 green; 10 blue, 4 red, 2 green; 6 green, 4 blue, 1 red; 10 blue, 2 red, 4 green
+Game 26: 7 green, 8 red, 6 blue; 5 red, 3 green, 2 blue; 13 blue, 6 green, 5 red; 10 blue, 4 red, 8 green; 2 red, 2 blue, 1 green; 8 blue, 1 green, 4 red
+Game 27: 7 green, 3 blue, 13 red; 1 green, 17 red, 1 blue; 16 red, 3 blue, 3 green; 5 green, 3 red, 5 blue; 13 red, 4 green, 8 blue; 6 blue, 2 green, 15 red
+Game 28: 8 blue, 5 red, 18 green; 1 green, 6 red; 7 blue, 18 green, 5 red; 16 green, 3 red, 7 blue; 6 blue, 18 green; 8 blue, 8 green, 7 red
+Game 29: 4 blue, 1 red; 6 blue, 1 red; 17 blue, 1 green
+Game 30: 1 red, 2 green, 5 blue; 2 blue, 7 green, 6 red; 11 blue, 4 red, 2 green; 5 green, 6 blue, 4 red; 5 red, 8 blue, 7 green
+Game 31: 10 green, 9 blue; 5 green, 9 blue, 1 red; 1 red, 8 blue
+Game 32: 3 red, 5 green; 5 red, 5 blue, 14 green; 2 red, 2 green; 11 green, 3 red, 5 blue
+Game 33: 7 blue, 10 green, 8 red; 18 blue, 15 green, 4 red; 6 red, 1 green; 18 blue, 8 red, 11 green
+Game 34: 3 green; 2 red, 5 green; 5 blue, 3 green; 3 blue, 5 green, 1 red
+Game 35: 1 blue, 5 green, 6 red; 3 green, 2 red, 3 blue; 4 red, 9 blue, 3 green; 1 green, 12 blue, 1 red
+Game 36: 14 green, 3 blue, 16 red; 1 green, 2 red, 4 blue; 4 blue, 9 green, 18 red; 4 blue, 4 green, 14 red; 4 blue, 11 green
+Game 37: 7 green, 2 blue, 3 red; 8 green, 9 red, 2 blue; 4 blue, 15 green, 18 red
+Game 38: 11 red, 1 blue, 6 green; 6 green, 2 blue, 1 red; 6 blue, 17 red, 2 green; 17 red, 9 blue, 3 green; 7 red, 7 blue, 3 green; 3 green, 7 red, 7 blue
+Game 39: 1 blue, 2 green; 1 blue, 2 green, 7 red; 1 blue, 4 red, 2 green; 1 blue, 12 red
+Game 40: 1 blue, 4 red, 15 green; 12 green, 1 blue, 15 red; 15 red, 8 green
+Game 41: 5 blue, 5 green, 1 red; 9 red, 8 green, 9 blue; 10 red, 10 blue, 4 green; 3 blue, 17 red, 3 green; 3 blue, 4 red, 2 green
+Game 42: 2 blue, 10 red, 17 green; 6 red, 10 green, 10 blue; 3 blue, 6 green, 8 red; 9 green, 2 blue, 8 red; 13 green, 5 blue; 4 red, 18 green, 11 blue
+Game 43: 8 red, 3 blue, 6 green; 2 red, 8 green, 10 blue; 5 blue, 9 red, 9 green; 1 green, 15 red, 8 blue
+Game 44: 11 green, 19 red, 14 blue; 1 red, 19 green, 9 blue; 7 green, 8 red, 10 blue; 14 green, 8 blue, 15 red; 7 green, 3 red, 2 blue
+Game 45: 4 green, 9 blue, 4 red; 7 blue, 13 green, 2 red; 12 green, 10 blue, 10 red
+Game 46: 10 red, 2 green, 1 blue; 10 red, 10 green, 1 blue; 1 blue, 13 green; 1 blue, 2 green, 10 red; 1 blue, 7 red, 11 green; 10 red, 5 green
+Game 47: 3 blue, 2 green, 12 red; 5 blue, 7 red; 5 green, 14 red; 12 red, 7 green, 5 blue
+Game 48: 5 red, 1 blue, 3 green; 7 red, 8 green, 4 blue; 4 blue, 5 green, 17 red; 1 blue, 12 red
+Game 49: 2 green, 7 red, 1 blue; 11 green, 5 red; 4 red, 1 blue, 1 green; 11 green, 1 blue, 7 red
+Game 50: 10 red, 3 blue, 6 green; 1 blue, 5 red, 3 green; 6 blue, 11 red, 12 green; 10 green
+Game 51: 18 blue, 1 green, 1 red; 15 blue; 13 blue, 11 green, 4 red; 8 red, 1 green, 18 blue; 10 green, 7 blue, 8 red
+Game 52: 13 green, 15 blue; 6 blue, 4 red, 8 green; 6 red, 13 green, 11 blue; 2 red, 7 green, 13 blue; 12 green, 2 blue, 3 red; 6 red, 11 green, 1 blue
+Game 53: 2 red, 2 green; 3 green, 1 blue, 1 red; 1 blue, 4 green, 7 red; 4 red, 1 blue; 4 red, 5 green, 2 blue
+Game 54: 8 blue, 2 red, 5 green; 6 green, 2 blue, 3 red; 1 blue, 8 green, 4 red
+Game 55: 6 green, 6 blue, 3 red; 13 green, 1 red; 2 blue, 1 red, 1 green; 14 green, 1 blue, 1 red; 1 blue, 2 red, 9 green; 9 green, 2 blue, 4 red
+Game 56: 4 green, 6 blue, 1 red; 5 red, 3 blue; 6 red, 1 blue; 9 green, 5 blue, 7 red
+Game 57: 5 red, 5 green, 8 blue; 11 red, 3 blue, 8 green; 7 green, 9 blue, 11 red; 3 green, 2 blue, 12 red
+Game 58: 3 green, 3 red; 4 red, 1 green; 1 red, 6 green; 5 green; 5 red, 1 blue, 3 green; 3 red, 1 blue
+Game 59: 2 green, 2 blue; 7 red, 18 green; 2 blue, 7 red, 16 green; 7 red, 10 green
+Game 60: 3 blue, 4 red; 4 blue, 3 red, 3 green; 16 green
+Game 61: 1 blue, 2 red, 8 green; 9 blue, 4 green, 12 red; 10 green, 2 red; 5 blue, 11 red, 1 green; 10 green, 3 blue, 8 red; 5 red, 2 green
+Game 62: 15 red, 10 blue, 7 green; 4 blue, 9 red, 4 green; 4 red, 2 blue, 2 green; 11 green, 2 red; 8 blue, 2 green; 2 green, 8 red, 8 blue
+Game 63: 2 green, 3 blue, 1 red; 7 blue, 5 red; 7 blue
+Game 64: 3 green, 5 blue, 6 red; 9 green, 4 red; 13 red, 1 blue, 5 green; 4 blue, 13 red, 8 green
+Game 65: 7 green, 1 blue; 1 red, 14 blue, 4 green; 8 blue, 6 red; 14 green, 4 red
+Game 66: 6 red, 11 green, 7 blue; 1 blue, 6 red; 13 red, 7 blue, 3 green; 8 red, 6 blue, 15 green; 7 green, 6 blue, 4 red; 4 red, 1 blue, 20 green
+Game 67: 4 blue, 9 green; 15 red, 16 green, 3 blue; 1 green, 14 red, 3 blue; 3 red, 2 blue, 3 green; 4 green, 3 blue, 12 red
+Game 68: 5 green, 3 blue, 2 red; 4 green, 8 blue, 11 red; 6 red, 6 blue, 4 green; 8 red, 5 blue, 7 green; 6 blue, 6 green, 11 red; 2 blue, 3 green, 3 red
+Game 69: 15 blue, 16 green, 5 red; 10 blue, 3 red, 13 green; 4 red, 5 blue, 2 green; 1 red; 11 green, 5 red, 15 blue
+Game 70: 8 red, 9 blue, 12 green; 3 red, 2 blue, 14 green; 10 blue, 1 red, 18 green; 1 blue, 7 red, 16 green; 3 green, 4 red, 16 blue; 10 green, 6 red
+Game 71: 12 blue, 7 red, 16 green; 2 red, 9 blue, 15 green; 1 red, 11 blue, 11 green; 15 red, 16 blue, 2 green
+Game 72: 1 blue, 11 red, 6 green; 1 red, 2 blue, 5 green; 4 green, 2 red; 2 green, 12 red
+Game 73: 1 blue, 1 red; 2 red, 4 blue, 2 green; 1 blue, 2 green, 10 red; 8 red
+Game 74: 12 red, 1 green, 4 blue; 1 red, 5 blue, 1 green; 11 green, 16 red, 7 blue; 7 red, 1 blue, 1 green; 12 red, 11 green, 12 blue; 11 green, 6 red
+Game 75: 12 green, 8 red, 3 blue; 7 red, 10 green; 1 green, 7 blue, 1 red
+Game 76: 4 green, 1 red, 3 blue; 7 blue, 3 green, 3 red; 4 blue, 2 red, 3 green; 4 blue, 1 green
+Game 77: 2 green, 12 blue, 10 red; 5 blue, 7 red; 2 red, 6 green; 1 blue, 2 red, 6 green
+Game 78: 2 green, 4 blue, 4 red; 8 green, 10 red, 10 blue; 5 green, 8 blue, 10 red; 6 green, 2 red
+Game 79: 3 green, 2 blue, 11 red; 8 red, 11 green, 1 blue; 1 blue, 16 red; 5 red, 7 green, 16 blue; 12 red, 7 green, 9 blue; 4 red, 20 blue, 12 green
+Game 80: 3 red, 5 green; 2 blue, 4 green; 2 red, 12 green, 4 blue; 10 green, 1 blue, 1 red; 4 blue, 3 red
+Game 81: 1 blue, 1 green, 1 red; 5 green, 3 red, 1 blue; 1 blue, 6 green; 1 green; 1 red, 5 green, 2 blue; 1 blue, 1 red, 3 green
+Game 82: 7 green, 10 blue, 3 red; 10 green, 12 red, 12 blue; 18 red, 8 green, 14 blue; 3 red, 3 green, 10 blue; 3 red, 1 blue, 5 green; 1 green, 8 blue
+Game 83: 9 red, 3 blue; 14 blue, 8 red, 3 green; 14 blue, 5 green, 4 red
+Game 84: 2 blue, 3 red, 6 green; 11 green, 2 red, 1 blue; 17 green, 3 blue, 3 red; 1 red, 1 blue; 1 red, 2 blue, 19 green
+Game 85: 3 green, 2 blue, 3 red; 4 red, 5 blue, 8 green; 15 green, 1 red, 9 blue; 12 green, 3 blue, 2 red
+Game 86: 15 green, 7 red, 10 blue; 2 blue, 2 red, 1 green; 4 red, 1 green, 9 blue; 7 red, 14 blue, 5 green
+Game 87: 1 green, 3 blue, 1 red; 2 blue, 1 green; 1 blue, 2 green, 1 red
+Game 88: 2 green, 6 blue, 5 red; 5 blue, 2 red; 3 red, 13 blue; 9 blue, 10 red, 1 green
+Game 89: 6 green, 10 red, 2 blue; 7 red, 1 blue, 8 green; 4 blue, 3 red, 5 green; 4 green, 4 blue, 10 red
+Game 90: 8 red, 7 blue; 4 green, 3 red, 1 blue; 5 blue, 2 green
+Game 91: 15 green, 14 red; 12 red, 16 green, 2 blue; 8 red, 10 green; 1 green, 6 red; 8 green, 12 red
+Game 92: 4 blue, 4 green, 9 red; 1 blue, 17 green; 1 green; 15 green, 3 blue, 12 red; 11 red, 1 blue, 7 green; 7 blue, 13 red, 8 green
+Game 93: 10 blue, 12 red; 10 blue, 11 green, 8 red; 1 blue, 11 green, 7 red; 10 blue, 15 red, 5 green; 11 red, 8 green, 9 blue; 10 green, 3 blue
+Game 94: 1 blue, 2 red; 4 red, 1 green, 5 blue; 3 red, 2 green; 2 green, 2 blue; 1 red, 5 blue, 1 green; 4 blue, 1 red, 2 green
+Game 95: 1 red, 1 blue, 3 green; 2 green, 6 blue; 1 green, 13 blue, 1 red; 3 green, 15 blue
+Game 96: 16 blue, 7 green, 5 red; 5 green, 5 blue, 6 red; 3 green, 17 blue, 10 red; 13 blue, 2 red, 1 green
+Game 97: 12 red; 1 blue, 6 red, 1 green; 9 red, 2 blue, 1 green; 1 green, 2 blue, 1 red; 15 red, 1 blue; 1 blue
+Game 98: 11 red, 6 blue, 13 green; 4 blue, 2 red, 12 green; 2 blue, 8 green, 10 red
+Game 99: 2 red, 1 blue; 4 green; 7 green, 1 blue, 1 red; 5 green, 2 red; 1 blue, 2 red, 9 green; 2 green, 3 red
+Game 100: 7 red, 11 blue; 10 red, 5 blue, 1 green; 7 red, 1 green, 13 blue; 9 red; 9 red, 19 blue; 9 red, 9 blue

input/day2-eg

@@ -0,0 +1,5 @@
+Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
+Game 2: 1 blue, 2 green; 3 green, 4 blue, 1 red; 1 green, 1 blue
+Game 3: 8 green, 6 blue, 20 red; 5 blue, 4 red, 13 green; 5 green, 1 red
+Game 4: 1 green, 3 red, 6 blue; 3 green, 6 red; 3 green, 15 blue, 14 red
+Game 5: 6 red, 1 blue, 3 green; 2 blue, 1 red, 2 green