+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
+
+
+import Data.Ratio
+import Data.List
+import qualified Data.Map.Strict as M
+import Data.Map.Strict ((!))
+import qualified Data.Set as S
+
+
+data Reagent = Reagent { _quantity :: Int, _chemical :: String } deriving (Ord, Eq, Show)
+data Rule = Rule {_lhs :: S.Set Reagent, _rhs :: Reagent} deriving (Eq, Show)
+
+type RuleBase = M.Map String Rule
+type Requirement = M.Map String Int
+
+
+main :: IO ()
+main = do
+ text <- TIO.readFile "data/advent14.txt"
+ let rules = successfulParse text
+ let ruleBase = mkRuleBase rules
+ -- print rules
+ -- print ruleBase
+ print $ part1 ruleBase
+ print $ part2 ruleBase
+
+oreLimit = 10^12
+
+mkRuleBase = foldl' addRule M.empty
+ where addRule base rule = M.insert (_chemical $ _rhs rule) rule base
+
+-- part1 rules = required!"ORE"
+-- where required0 = M.singleton "FUEL" 1
+-- required = produce rules required0
+part1 rules = oreForFuel rules 1
+
+part2 rules = searchFuel rules 1 upper
+ where upper = findUpper rules (oreLimit `div` base)
+ base = oreForFuel rules 1
+
+
+oreForFuel rules n = required!"ORE"
+ where required0 = M.singleton "FUEL" n
+ required = produce rules required0
+
+findUpper _ n | trace ("Upper " ++ show n) False = undefined
+findUpper rules n = if ore > oreLimit
+ then n
+ else findUpper rules (n * 2)
+ where ore = oreForFuel rules n
+
+searchFuel _ lower upper | trace ("Search " ++ show lower ++ " - " ++ show upper) False = undefined
+searchFuel rules lower upper
+ | upper == lower = upper
+ | otherwise = if ore > oreLimit
+ then searchFuel rules lower mid
+ else searchFuel rules mid upper
+ where mid = (upper + lower) `div` 2
+ ore = oreForFuel rules mid
+
+
+produce :: RuleBase -> Requirement -> Requirement
+produce rules required
+ | M.null outstanding = required
+ | otherwise = produce rules required''
+ where outstanding = M.filter (> 0) $ nonOre required
+ (chem, qty) = M.findMin outstanding
+ rule = rules!chem
+ qty' = qty - (_quantity $ _rhs rule)
+ required' = M.insert chem qty' required
+ required'' = S.foldl addRequrirement required' (_lhs rule)
+
+
+nonOre :: Requirement -> Requirement
+nonOre = M.filterWithKey (\c _ -> c /= "ORE")
+
+
+addRequrirement :: Requirement -> Reagent -> Requirement
+addRequrirement requirements reagent = M.insert chem qty' requirements
+ where chem = _chemical reagent
+ qty = M.findWithDefault 0 chem requirements
+ qty' = qty + (_quantity reagent)
+
+
+-- 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
+integer = lexeme L.decimal
+-- signedInteger = L.signed sc integer
+symb = L.symbol sc
+arrowP = symb "=>"
+commaP = symb ","
+identifierP = some alphaNumChar <* sc
+
+
+rulesP = many ruleP
+
+ruleP = Rule <$> reagentsP <* arrowP <*> reagentP
+
+reagentP = Reagent <$> integer <*> identifierP
+reagentsP = S.fromList <$> reagentP `sepBy` commaP
+
+-- successfulParse :: Text -> [Vec]
+successfulParse :: Text -> [Rule]
+successfulParse input =
+ case parse rulesP "input" input of
+ Left _err -> [] -- TIO.putStr $ T.pack $ parseErrorPretty err
+ Right rules -> rules
projects / advent-of-code-19.git / commitdiff