day 2 is done

README.md

@@ -11,7 +11,7 @@ Solutions, scripting, and templates - all in one repo.
 
 | `<++++++++>` | `<++++++++>` | `<++++++++>` | `<++++++++>` | `<++++++++>` |
 | :-: | :-: | :-: | :-: | :-: |
-| ☑ [Day 1](src/Javran/AdventOfCode/Y2023/Day1.hs) |  |  |  |  |
+| ☑ [Day 1](src/Javran/AdventOfCode/Y2023/Day1.hs) | ☐ [Day 2](src/Javran/AdventOfCode/Y2023/Day2.hs) |  |  |  |
 
 ### 2022
 

data/testdata/2023/day/2/example.expect.txt

@@ -0,0 +1,2 @@
+8
+2286

data/testdata/2023/day/2/example.input.txt

@@ -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

src/Javran/AdventOfCode/Solutions.hs

@@ -212,6 +212,7 @@ import Javran.AdventOfCode.Y2022.Day23 ()
 import Javran.AdventOfCode.Y2022.Day24 ()
 import Javran.AdventOfCode.Y2022.Day25 ()
 import Javran.AdventOfCode.Y2023.Day1 ()
+import Javran.AdventOfCode.Y2023.Day2 ()
 {- ORMOLU_ENABLE -}
 
 allSolutions :: IM.IntMap (IM.IntMap SomeSolution)

src/Javran/AdventOfCode/Y2023/Day2.hs

@@ -0,0 +1,55 @@
+{-# LANGUAGE PatternSynonyms #-}
+
+module Javran.AdventOfCode.Y2023.Day2 () where
+
+import Data.Monoid hiding (First, Last)
+import Data.Semigroup
+import Javran.AdventOfCode.Prelude
+import Text.ParserCombinators.ReadP hiding (count, get, many)
+
+data Day2 deriving (Generic)
+
+newtype Rgb a = Rgb (a, a, a)
+  deriving stock (Show)
+  deriving (Semigroup) via (Sum a, Sum a, Sum a)
+  deriving (Monoid) via (Sum a, Sum a, Sum a)
+
+type GameLine = [Rgb Int]
+
+oneSetP :: ReadP (Rgb Int)
+oneSetP =
+  mconcat <$> do
+    numAndCubeP `sepBy1` strP ", "
+  where
+    numAndCubeP = do
+      n <- decimal1P
+      strP " "
+      (Rgb (n, 0, 0) <$ strP "red")
+        <++ (Rgb (0, n, 0) <$ strP "green")
+        <++ (Rgb (0, 0, n) <$ strP "blue")
+
+gameLineP :: ReadP (Int, GameLine)
+gameLineP = do
+  strP "Game "
+  n <- decimal1P @Int
+  strP ": "
+  (n,) <$> oneSetP `sepBy1` strP "; "
+
+{-
+  It would be neat if this sort of thing can be put in some general library instead of us having to
+  declare it here - which makes it a bit more too verbose to my liking.
+ -}
+pattern MaxRgb :: a -> a -> a -> (Max a, Max a, Max a)
+pattern MaxRgb r g b = (Max r, Max g, Max b)
+
+findPower :: GameLine -> Int
+findPower = (\(MaxRgb r g b) -> r * g * b) . foldMap (\(Rgb (r, g, b)) -> MaxRgb r g b)
+
+instance Solution Day2 where
+  solutionSolved _ = True
+  solutionRun _ SolutionContext {getInputS, answerShow} = do
+    xs <- fmap (consumeOrDie gameLineP) . lines <$> getInputS
+    answerShow $
+      let isPossible (Rgb (r, g, b)) = r <= 12 && g <= 13 && b <= 14
+       in getSum $ foldMap (\(which, ys) -> if all isPossible ys then Sum which else 0) xs
+    answerShow $ getSum $ foldMap (Sum . findPower . snd) xs