X-Git-Url: https://git.njae.me.uk/?p=advent-of-code-19.git;a=blobdiff_plain;f=advent12%2Fsrc%2Fadvent12.hs;fp=advent12%2Fsrc%2Fadvent12.hs;h=b847d28de03b194954589d30b0e26f14d19b4565;hp=0000000000000000000000000000000000000000;hb=64e7414bf1a3d2391383c4d5c55180d2c7950c9d;hpb=8647f68ff73192d6e13314afbf4ed3b498c4d284

diff --git a/advent12/src/advent12.hs b/advent12/src/advent12.hs
new file mode 100644
index 0000000..b847d28
--- /dev/null
+++ b/advent12/src/advent12.hs
@@ -0,0 +1,100 @@
+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 Linear (V3(..), (^+^), (^-^))
+
+import qualified Data.Set as S
+
+-- import Data.List (foldl')
+-- import Data.Set ((\\))
+-- import qualified Data.Map.Strict as M
+-- import Data.Map.Strict ((!))
+
+
+type Vec = V3 Integer
+data Planet = Planet { _pos :: Vec, _vel :: Vec} deriving (Show, Eq, Ord)
+type Planets = S.Set Planet
+
+
+main :: IO ()
+main = do 
+        text <- TIO.readFile "data/advent12a.txt"
+        let planetsT = successfulParse text
+        let planets = enplanet planetsT
+        print planets
+        print $ part1 planets
+
+
+part1 planets = take 12 $ simulate planets
+
+
+enplanet  = S.fromList . map (\p -> Planet {_pos = p, _vel = (V3 0 0 0)} )
+
+_x (V3 x _ _) = x
+_y (V3 _ y _) = y
+_z (V3 _ _ z) = z
+
+
+gravity (V3 x y z) = V3 (signum x) (signum y) (signum z)
+
+
+simulate = iterate simulationStep 
+
+simulationStep planets = planets''
+    where   planets' = applyGravity planets
+            planets'' = applyVelocity planets'
+
+
+applyGravity planets = S.map (applyGravityHere planets) planets
+
+applyGravityHere planets here = S.foldl' updateGravity here planets
+
+updateGravity here there = here { _vel = vel'}
+    where   vel = _vel here
+            vel' = vel ^+^ gravity ((_pos there) ^-^ (_pos here))
+
+
+applyVelocity = S.map applyVelocityHere
+
+applyVelocityHere here = here {_pos = (_pos here) ^+^ (_vel here)}
+
+
+
+-- 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
+equalP = symb "="
+commaP = symb ","
+identifierP = some alphaNumChar <* sc
+openBracketP = symb "<"
+closeBracketP = symb ">"
+
+planetsP = many planetP
+
+planetP = (between openBracketP closeBracketP) coordsP
+
+coordsP = envector <$> (coordP `sepBy` commaP)
+    where envector [x, y, z] = V3 x y z
+coordP = identifierP *> equalP *> signedInteger
+
+
+successfulParse :: Text -> [Vec]
+successfulParse input = 
+        case parse planetsP "input" input of
+                Left  _err -> [] -- TIO.putStr $ T.pack $ parseErrorPretty err
+                Right planets -> planets
\ No newline at end of file