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module Main where
import Text.ParserCombinators.Parsec
import Text.Parsec.Char
countElem c ls = sum $ map (fromEnum . (== c)) ls
xor a b = (not a && b) || (a && not b)
right (Right a) = a
data PassProp = PassProp
{ range :: (Int, Int)
, c :: Char
, pass :: String
} deriving (Show)
parseProp :: Parser PassProp
parseProp = do
lower <- many1 digit
upper <- char '-' >> many1 digit
c <- space >> letter
password <- string ": " >> many letter
return $ PassProp (read lower, read upper) c password
doCheck1 :: PassProp -> Bool
doCheck1 PassProp { range = (lower, upper), c = c, pass = pass} =
count >= lower && count <= upper
where count = countElem c pass
doCheck2 :: PassProp -> Bool
doCheck2 PassProp { range = (lower, upper), c = c, pass = pass} =
(pass !! (lower - 1) == c) `xor` (pass !! (upper - 1) == c)
parseLine :: Parser a -> String -> a
parseLine parser line = right $ parse parser "input" line
main :: IO ()
main = do
n <- map (parseLine parseProp) . lines <$> readFile "input/02"
print $ countElem True (map doCheck1 n)
print $ countElem True (map doCheck2 n)
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