29 lines
923 B
Haskell
29 lines
923 B
Haskell
import Data.HashSet (Set, fromList, delete)
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import Data.List.Split
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type Weight = Int
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type Program = String
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type Programs = [Program]
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discardEmpty :: [String] -> [String]
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discardEmpty [""] = []
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discardEmpty xs = xs
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parseLine :: String -> (Program, Weight, Programs)
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parseLine line =
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let nameAndWeight : programsString : _ = splitOn ")" line
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programs = discardEmpty $ splitOn ", " $ last $ splitOn " -> " programsString
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name : weight : _ = splitOn " (" nameAndWeight
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in (name, read weight, programs)
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main :: IO ()
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main = do
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input <- readFile "7.txt"
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let list = map parseLine $ lines input
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nameSet = fromList $ map (\(name, _, _) -> name) list
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bottom = foldr (\(name, _, programs) set ->
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case programs of
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[] -> delete name set
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ps -> foldr delete set ps)
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nameSet list
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print $ bottom |