108 lines
2.6 KiB
Haskell
108 lines
2.6 KiB
Haskell
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-- a haiku:
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-- this is some bad code
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-- but what more can you expect
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-- from a bad problem?
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import Data.Char (isDigit, isHexDigit)
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import Data.List (sort, nub)
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main :: IO ()
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main = do
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raw <- readFile "day4.txt"
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let ls = parse $ lines raw
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ansA = length $ filter (== True) $ map solveA ls
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ansB = length $ filter (== True) $ map solveB ls
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in do
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putStrLn $ "day3a: " ++ (show ansA)
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putStrLn $ "day3b: " ++ (show ansB)
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rtags :: [String]
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rtags = ["byr", "iyr", "eyr", "hgt", "hcl", "ecl", "pid"]
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extractTag :: String -> String
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extractTag [] = error "empty tag"
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extractTag s = takeWhile (/= ':') s
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extractValue :: String -> String
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extractValue [] = error "empty value"
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extractValue s = drop 1 $ dropWhile (/= ':') s
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applyAll :: [a] -> [(a -> b)] -> [b]
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applyAll [] [] = []
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applyAll (a:as) (f:fs) =
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if length as /= length fs
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then error "applyAll: lists must be same length"
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else (f a) : (applyAll as fs)
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solveA :: [String] -> Bool
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solveA [] = False
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solveA s = foldr (&&) True $ map (`elem` tags) rtags
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where
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tags = map extractTag s
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solveB :: [String] -> Bool
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solveB [] = False
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solveB s = solveA s &&
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(foldr (&&) True $ applyAll ls
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[ byrValid
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, eclValid
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, eyrValid
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, hclValid
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, hgtValid
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, iyrValid
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, pidValid
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])
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where
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ls = (sort . nub) $ filter (\x -> elem (extractTag x) rtags) s
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yearValid :: Int -> Int -> String -> Bool
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yearValid l u s' = (length s) == 4
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&& (read s) >= l
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&& (read s) <= u
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where
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s = drop 1 $ dropWhile (/= ':') s'
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byrValid :: String -> Bool
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byrValid = yearValid 1920 2002
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iyrValid :: String -> Bool
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iyrValid = yearValid 2010 2020
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eyrValid :: String -> Bool
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eyrValid = yearValid 2020 2030
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eclValid :: String -> Bool
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eclValid s' = s `elem` ["amb","blu","brn","gry","grn","hzl","oth"]
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where
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s = drop 1 $ dropWhile (/= ':') s'
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pidValid :: String -> Bool
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pidValid s' = (length s) == 9 && all isDigit s
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where
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s = drop 1 $ dropWhile (/= ':') s'
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hclValid :: String -> Bool
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hclValid s' = h == '#' && all isHexDigit s
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where
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(h:s) = drop 1 $ dropWhile (/= ':') s'
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hgtValid :: String -> Bool
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hgtValid s' =
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case unit of
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"cm" -> val >= 150 && val <= 193
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"in" -> val >= 59 && val <= 76
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_ -> False
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where
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s = drop 1 $ dropWhile (/= ':') s'
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(val,unit) = head $ (reads s :: [(Int,String)])
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parse :: [String] -> [[String]]
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parse [] = []
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parse s = parse' s [] []
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parse' :: [String] -> [String] -> [[String]] -> [[String]]
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parse' [] as bs = bs ++ [as]
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parse' (s:ss) as bs
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| s == "" = parse' ss [] $ bs ++ [as]
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| otherwise = parse' ss (as ++ (words s)) bs
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