X-Git-Url: https://git.njae.me.uk/?p=advent-of-code-20.git;a=blobdiff_plain;f=advent07%2Fsrc%2Fadvent07.hs;fp=advent07%2Fsrc%2Fadvent07.hs;h=ee7a514688162f73a8ef78d01e3e6a5694789136;hp=0000000000000000000000000000000000000000;hb=33ea1e47e48b789d631f543e48f37287f58ffc96;hpb=a391f550e2af9522e1c64d7695b4fa60257ca3a6

diff --git a/advent07/src/advent07.hs b/advent07/src/advent07.hs
new file mode 100644
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+++ b/advent07/src/advent07.hs
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+-- import Debug.Trace
+
+import Data.Text (Text)
+import qualified Data.Text as T
+import qualified Data.Text.IO as TIO
+
+import Data.Attoparsec.Text
+-- import Data.Attoparsec.Combinator
+import Control.Applicative
+
+import qualified Data.Set as S
+import qualified Data.Map.Strict as M
+import Data.Map.Strict ((!))
+
+import Data.Maybe
+
+data QuantifiedBag = QuantifiedBag Integer String
+    deriving (Show, Eq, Ord)
+
+
+main :: IO ()
+main = 
+  do  text <- TIO.readFile "data/advent07.txt"
+      let bags = successfulParse text
+      -- print bags
+      -- print $ invertBags bags
+      print $ part1 bags
+      print $ part2 bags
+
+part1 bags = S.size $ S.delete "shiny gold" containers
+    where containers = bagsContaining (invertBags bags) (S.singleton "shiny gold") S.empty
+
+part2 bags = (nContainedBags bags "shiny gold") - 1
+
+invertBags bags = foldr addInvert M.empty $ concatMap swapPair $ M.assocs bags 
+    where swapPair (a, bs) = [(qName b, a) | b <- S.toList bs]
+
+addInvert :: (String, String) -> (M.Map String (S.Set String)) -> (M.Map String (S.Set String))
+addInvert (k, v) m = 
+    if k `M.member` m
+    then M.insert k v' m
+    else M.insert k (S.singleton v) m
+    where v' = S.insert v (m!k)
+
+qName (QuantifiedBag _ n) = n
+qCount (QuantifiedBag n _) = n
+
+bagsContaining :: (M.Map String (S.Set String)) -> (S.Set String) -> (S.Set String) -> (S.Set String)
+bagsContaining iBags agenda result 
+    | S.null agenda = result
+    | otherwise = bagsContaining iBags agenda'' (S.insert thisColour result)
+    where thisColour = S.findMin agenda
+          agenda' = S.delete thisColour agenda
+          agenda'' = if thisColour `S.member` result
+                     then agenda'
+                     else S.union (fromMaybe S.empty (M.lookup thisColour iBags)) agenda' 
+
+nContainedBags :: (M.Map String (S.Set QuantifiedBag)) -> String -> Integer
+nContainedBags bags thisBag = 1 + (sum $ map subCount others)
+    where others = S.toList $ bags!thisBag
+          subCount b = (qCount b) * (nContainedBags bags (qName b))
+
+
+
+-- -- Parse the input file
+
+bagNameP = manyTill anyChar ((string " bags") <|> (string " bag"))
+
+quantifiedBagP = QuantifiedBag <$> decimal <* space <*> bagNameP
+
+emptyBagListP = "no other bags" *> pure S.empty
+
+bagListP = S.fromList <$> sepBy quantifiedBagP (string ", ")
+
+bagContentsP = emptyBagListP <|> bagListP
+
+ruleP = (,) <$> bagNameP <* " contain " <*> bagContentsP <* "."
+
+rulesP = M.fromList <$> sepBy ruleP endOfLine
+
+
+
+-- successfulParse :: Text -> [[S.Set Char]]
+successfulParse input = 
+  case parseOnly rulesP input of
+    Left  _err -> M.empty -- TIO.putStr $ T.pack $ parseErrorPretty err
+    Right bags -> bags