X-Git-Url: https://git.njae.me.uk/?p=advent-of-code-20.git;a=blobdiff_plain;f=advent07%2Fsrc%2Fadvent07graph.hs;fp=advent07%2Fsrc%2Fadvent07graph.hs;h=ee31c811b915bd0fdd37f35a7e1b5b5ebff30d2f;hp=0000000000000000000000000000000000000000;hb=072b9c66fc1e67fb78106ada274a6e6b0137c50f;hpb=bb87fe8d48a7debc85dcbff2c08a7d8267427a77

diff --git a/advent07/src/advent07graph.hs b/advent07/src/advent07graph.hs
new file mode 100644
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+++ b/advent07/src/advent07graph.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.Graph.DGraph as D
+import qualified Data.Graph.Types as G
+import qualified Data.Graph.Traversal as T
+
+import qualified Data.Set as S
+import qualified Data.Map.Strict as M
+
+data QuantifiedBag = QuantifiedBag Int String
+    deriving (Show, Eq, Ord)
+
+type QBags = S.Set QuantifiedBag
+type BagRules = M.Map String QBags
+type BagGraph = D.DGraph String Int
+
+
+main :: IO ()
+main = 
+  do  text <- TIO.readFile "data/advent07.txt"
+      let bags = successfulParse text
+      let graph = buildGraph bags
+      -- print graph
+      -- dumpBagDot bags
+      print $ part1 graph
+      print $ part2 graph
+
+part1 graph = length (T.bfsVertices (D.transpose graph) "shiny gold") - 1
+
+part2 graph = (bfsCount graph "shiny gold") - 1
+
+bfsCount :: BagGraph -> String -> Int
+bfsCount graph thisBag = 1 + (sum $ map subCount others)
+    where others = D.outboundingArcs graph thisBag
+          subCount a = (G.attribute a) * (bfsCount graph $ G.destinationVertex a)
+
+
+buildGraph :: BagRules -> BagGraph
+buildGraph rules = M.foldrWithKey addRule G.empty rules
+
+addRule :: String -> QBags -> BagGraph -> BagGraph
+addRule source dests graph = S.foldr (addArc source) graph dests
+
+addArc :: String -> QuantifiedBag -> BagGraph -> BagGraph
+addArc source (QuantifiedBag quantity destination) graph = D.insertArc arc graph
+  where arc = G.Arc source destination quantity
+
+
+-- dumpBagDot bags = 
+--     do writeFile "a07dump.dot" "digraph {\n"
+--        mapM_ dumpABag (M.assocs bags)
+--        appendFile "a07dump.dot" "shiny_gold [fillcolor = gold1 ]\n"
+--        appendFile "a07dump.dot" "}\n"
+
+-- dumpABag (bag, contents) =
+--     mapM_ (dumpALink bag) (S.toList contents)
+
+-- dumpALink bag (QuantifiedBag n name) =
+--     do  let name' = squashName name
+--         let bag' = squashName bag
+--         let txt = bag' ++ " -> " ++ name' ++ "\n"
+--         appendFile "a07dump.dot" txt
+
+-- squashName :: String -> String
+-- squashName name = [if c == ' ' then '_' else c | c <- name]
+
+
+-- -- 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 -> BagRules
+successfulParse input = 
+  case parseOnly rulesP input of
+    Left  _err -> M.empty -- TIO.putStr $ T.pack $ parseErrorPretty err
+    Right bags -> bags