98 lines
3.6 KiB
Haskell
98 lines
3.6 KiB
Haskell
import AoC
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import Control.Applicative ((<|>))
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import Control.Monad (guard, mfilter)
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import Data.Char (isDigit)
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import Data.List (intercalate)
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import Data.Maybe (mapMaybe)
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import Text.ParserCombinators.ReadP
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import Text.Read (readMaybe)
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data HeightUnit = Centimeter | Inch deriving (Show, Eq)
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data ColourSpec = Amber | Blue | Brown | Gray | Green | Hazel | Other
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deriving (Show, Eq)
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data Field = BirthYear Int
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| IssueYear Int
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| ExpirationYear Int
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| Height Int HeightUnit
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| HairColour String
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| EyeColour ColourSpec
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| PassportID String
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| CountryID String
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deriving (Show, Eq)
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fieldSpecs :: [(String, ReadP Field)]
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fieldSpecs = [ ("byr", BirthYear <$> parseYearIn 1920 2002)
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, ("iyr", IssueYear <$> parseYearIn 2010 2020)
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, ("eyr", ExpirationYear <$> parseYearIn 2020 2030)
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, ("hgt", do h <- parseNumber 2 <|> parseNumber 3
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u <- parseHeightUnit
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case u of
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Inch -> guard $ within 59 76 h
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Centimeter -> guard $ within 150 193 h
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return $ Height h u)
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, ("hcl", char '#' >> HairColour <$> count 6 parseHexDigit)
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, ("ecl", EyeColour <$> parseColourSpec)
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, ("pid", PassportID <$> count 9 (satisfy $ const True))
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, ("cid", CountryID <$> munch1 (/= ' '))
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]
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where parseYearIn = flip mfilter (parseNumber 4) .: within
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parseHexDigit = choice . map char $ ['0'..'9']++['a'..'f']
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within :: Ord a => a -> a -> a -> Bool
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within a b x = a <= x && x <= b
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parseNumber :: (Num a, Read a) => Int -> ReadP a
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parseNumber n = do
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Just digits <- readMaybe <$> count n (satisfy isDigit)
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return digits
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parseHeightUnit :: ReadP HeightUnit
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parseHeightUnit = choice [ string "cm" >> return Centimeter
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, string "in" >> return Inch
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]
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parseColourSpec :: ReadP ColourSpec
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parseColourSpec = choice [ string "amb" >> return Amber
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, string "blu" >> return Blue
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, string "brn" >> return Brown
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, string "gry" >> return Gray
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, string "grn" >> return Green
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, string "hzl" >> return Hazel
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, string "oth" >> return Other
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]
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parseKeyValue :: ReadP k -> ReadP v -> ReadP (k, v)
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parseKeyValue kp vp = do k <- kp
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char ':'
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v <- vp
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return (k, v)
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parseFieldName :: ReadP String
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parseFieldName = fmap fst $ choice
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$ map (\(k, _) -> parseKeyValue (string k) (munch1 (/= ' ')))
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$ fieldSpecs
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parseField :: ReadP Field
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parseField = fmap snd $ choice
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$ map (\(k, v) -> parseKeyValue (string k) v)
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$ fieldSpecs
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spaceSeparated :: ReadP a -> ReadP [a]
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spaceSeparated = flip sepBy (many1 $ char ' ')
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parseFieldNames :: ReadP [String]
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parseFieldNames = spaceSeparated parseFieldName
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parsePassport :: ReadP [Field]
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parsePassport = spaceSeparated parseField
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hasAllRequiredFields :: String -> Bool
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hasAllRequiredFields = maybe False containsAllFields . fieldNames
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where requiredFieldNames = ["byr", "iyr", "eyr", "hgt", "hcl", "ecl", "pid"]
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containsAllFields fields = all (`elem` fields) requiredFieldNames
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fieldNames = oneCompleteResult parseFieldNames
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main = runAoC (filter hasAllRequiredFields . map unwords . splitOnEmptyLines) length (length . mapMaybe (oneCompleteResult parsePassport))
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