Day12: Part 2 works

day12.hs

@@ -5,10 +5,18 @@ import Linear.V3
 
 main = do
       moons <- map createMoon <$> map getList <$> map cleanString <$> lines <$> getContents
-      let newMoons = stepMoons moons 1000
-      let ernergy = sum $ map getErnergy newMoons
-      mapM putStrLn ( map show newMoons )
-      putStrLn ( show ernergy)
+      --let newMoons = calculateMoons moons 1000
+      --let ernergy = sum $ map getErnergy newMoons
+      let xAxis = getXAxis moons
+      let loopx = findLoop xAxis xAxis 0
+      let yAxis = getYAxis moons 
+      let loopy = findLoop yAxis yAxis 0
+      let zAxis = getZAxis moons 
+      let loopz = findLoop zAxis zAxis 0
+      let result = foldl1 lcm [loopx, loopy, loopz] 
+      --mapM putStrLn ( map show newMoons )
+      --putStrLn ( show ernergy)
+      putStrLn(show result)
 
 data Moon = Moon{ position :: V3 Int
                   ,velocity :: V3 Int
@@ -28,18 +36,54 @@ stepGravity xs = map (\(p,v) -> Moon p v) $ zip (newPos) newVel
             where newVel = zipWith (+) (getVel xs) (gravity $ getPos xs)
                   newPos = zipWith (+) (getPos xs) (newVel)  
 
+gravity :: (Num a, Eq a)=> [a] -> [a]
+gravity xs = [sum [signum $ x-y | x<-xs, y/=x] | y<-xs]
+
+calculateMoons :: [Moon] -> Int -> [Moon]
+calculateMoons xs 0 = xs
+calculateMoons xs n = calculateMoons (stepGravity xs) (n-1)
+
+findLoop :: ([Int],[Int]) -> ([Int],[Int]) -> Int -> Int
+findLoop pos start c  
+     | pos /= start || c == 0 = findLoop (stepAxis pos) start (c+1)
+     | pos == start = c
+
+stepAxis :: ([Int],[Int]) -> ([Int],[Int])
+stepAxis (pos,vel) = (newPos, newVel)
+         where newVel = zipWith (+) (vel) (gravity pos)
+               newPos = zipWith (+) (pos) (newVel)
+
 getPos :: [Moon] -> [V3 Int]
 getPos xs = map(\x -> position x) xs
 
 getVel :: [Moon] -> [V3 Int]
 getVel xs = map(\x -> velocity x) xs
 
-gravity :: [V3 Int] -> [V3 Int]
-gravity xs = [sum [signum $ x-y | x<-xs, y/=x] | y<-xs]
-
-stepMoons :: [Moon] -> Int -> [Moon]
-stepMoons xs 0 = xs
-stepMoons xs n = stepMoons (stepGravity xs) (n-1)
-
 getErnergy :: Moon -> Int
 getErnergy (Moon pos vel)  = (sum $ abs pos) * (sum $ abs vel)
+
+getXAxis :: [Moon] -> ([Int],[Int])
+getXAxis xs = (pos,vel)
+           where   pos = map(\x -> getX $ position x) xs
+                   vel = map(\x -> getX $ velocity x) xs
+
+getZAxis :: [Moon] -> ([Int],[Int])
+getZAxis xs = (pos,vel)
+           where   pos = map(\x -> getZ $ position x) xs
+                   vel = map(\x -> getZ $ velocity x) xs
+
+getYAxis :: [Moon] -> ([Int],[Int])
+getYAxis xs = (pos,vel)
+           where   pos = map(\x -> getY $ position x) xs
+                   vel = map(\x -> getY $ velocity x) xs
+
+getX :: V3 Int -> Int
+getX (V3 x y z) = x
+
+getY :: V3 Int -> Int
+getY (V3 x y z) = y
+
+getZ :: V3 Int -> Int
+getZ (V3 x y z) = z
+
+