X-Git-Url: https://git.njae.me.uk/?p=advent-of-code-20.git;a=blobdiff_plain;f=advent02%2Fsrc%2Fadvent02.hs;fp=advent02%2Fsrc%2Fadvent02.hs;h=27886d05744f8c57507ef52f379f24b6e0b7f1fa;hp=0000000000000000000000000000000000000000;hb=72c69da4bb83a1a18965411c7a52b3f9b3a18d2d;hpb=d3f84f094ba00f34cd43eea17a7aab4200a8ef04

diff --git a/advent02/src/advent02.hs b/advent02/src/advent02.hs
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+++ b/advent02/src/advent02.hs
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+-- import Debug.Trace
+
+import Data.Text (Text)
+import qualified Data.Text.IO as TIO
+
+import Data.Void (Void)
+
+import Text.Megaparsec hiding (State)
+import Text.Megaparsec.Char
+import qualified Text.Megaparsec.Char.Lexer as L
+import qualified Control.Applicative as CA
+
+data Policy = Policy
+  { lower :: Int
+  , upper :: Int
+  , character :: Char
+  , password :: String    
+  } deriving (Show, Eq, Ord)
+
+main :: IO ()
+main = 
+  do  text <- TIO.readFile "data/advent02.txt"
+      let policies = successfulParse text
+      print $ part1 policies
+      print $ part2 policies
+      -- print $ head $ part2 nums
+
+part1 = length . filter inRange
+  where nCharsPresent p = length $ filter (== (character p)) (password p)
+        inRange p = (nCharsPresent p >= (lower p)) && (nCharsPresent p <= (upper p))
+
+part2 = length . filter matches
+
+matches p = ((pw!!l) == c) /= ((pw!!u) == c)
+  where pw = password p
+        c = character p
+        l = (lower p) - 1
+        u = (upper p) - 1
+
+
+-- Parse the input file
+type Parser = Parsec Void Text
+
+sc :: Parser ()
+sc = L.space (skipSome spaceChar) CA.empty CA.empty
+-- sc = L.space (skipSome (char ' ')) CA.empty CA.empty
+
+lexeme  = L.lexeme sc
+integerP = lexeme L.decimal
+-- signedInteger = L.signed sc integer
+symb = L.symbol sc
+hyphenP = symb "-"
+colonP = symb ":"
+characterP = alphaNumChar <* sc
+passwordP = some alphaNumChar <* sc
+
+policiesP = many policyP
+policyP = Policy <$> integerP <* hyphenP <*> integerP <*> characterP <* colonP <*> passwordP
+-- policyP = (,,,) <$> integerP <* hyphenP <*> integerP <*> characterP <* colonP <*> passwordP
+
+-- successfulParse :: Text -> [Policy]
+successfulParse input = 
+  case parse policiesP "input" input of
+    Left  _err -> [] -- TIO.putStr $ T.pack $ parseErrorPretty err
+    Right policies -> policies