eldridge.cam
Advent of Code solutions
2020:21
+56
-1
+22
2020/21/p1.hs
+22
2020/21/p1.hs
···
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import Text.Parsec
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import Data.Set qualified as Set
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import Data.Set ((\\))
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import Data.Map.Strict qualified as Map
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import Data.List (foldl1)
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food = do
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ingredients <- many1 letter `endBy` char ' '
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string "(contains "
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allergens <- many1 letter `sepBy` string ", "
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char ')'
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return (ingredients, allergens)
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answer contents = length $ filter (`elem` safe) $ concat $ (fst <$> foods)
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where
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Right foods = parse (food `endBy` newline) "" contents
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allergens = Set.unions (Set.fromList <$> snd <$> foods)
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ingredients = Set.unions (Set.fromList <$> fst <$> foods)
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candidates = Map.fromList $ Set.toList allergens `zip` fmap (\a -> foldl1 Set.intersection $ fmap (Set.fromList . fst) $ filter (\(_, i) -> a `elem` i) foods) (Set.toList allergens)
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safe = Set.toList $ ingredients \\ (Set.unions $ Map.elems candidates)
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main = getContents >>= print . answer
+32
2020/21/p2.hs
+32
2020/21/p2.hs
···
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import Text.Parsec
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import Data.Bifunctor
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import Data.Set qualified as Set
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import Data.Set (Set)
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import Data.Map.Strict qualified as Map
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import Data.Map (Map)
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import Data.List
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food = do
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ingredients <- many1 letter `endBy` char ' '
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string "(contains "
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allergens <- many1 letter `sepBy` string ", "
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char ')'
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return (ingredients, allergens)
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solve :: [(String, Set String)] -> Map String String
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solve [] = Map.empty
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solve candidates = Map.fromList singles `Map.union` rest
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where
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singles = second Set.findMin <$> filter (\(_, c) -> Set.size c == 1) candidates
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eliminating = snd <$> singles
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eliminate = Set.filter (`notElem` eliminating)
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rest = solve $ filter (not . null . snd) $ fmap (second eliminate) candidates
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answer contents = intercalate "," $ Map.elems $ solve candidates
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where
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Right foods = parse (food `endBy` newline) "" contents
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allergens = Set.unions (Set.fromList <$> snd <$> foods)
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ingredients = Set.unions (Set.fromList <$> fst <$> foods)
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candidates = Set.toList allergens `zip` fmap (\a -> foldl1 Set.intersection $ fmap (Set.fromList . fst) $ filter (\(_, i) -> a `elem` i) foods) (Set.toList allergens)
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main = getContents >>= putStrLn . answer
+2
-1
Justfile
+2
-1
Justfile
···
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set quiet
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set shell := ["fish", "-c"]
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-
default_year := "2024"
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default_year := env_var_or_default("YEAR", "2024")
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session := env_var("SESSION")
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[no-cd]
···
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end
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get day year=default_year:
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echo "Getting {{year}} day {{day}}"
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mkdir -p {{year}}/{{day}}
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curl https://adventofcode.com/{{year}}/day/{{day}}/input \
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-X GET \