1 files changed, 37 insertions, 0 deletions
diff --git a/day06/main.hs b/day06/main.hs
new file mode 100644
index 0000000..fd310c0
--- /dev/null
+++ b/day06/main.hs
@@ -0,0 +1,37 @@
+module Main where
+
+import Data.Map ((!))
+import qualified Data.Map as Map
+import Data.Text (pack, split, unpack)
+import Utils
+
+e1 :: Int -> [Int] -> Int
+e1 n fish
+  | n == 0 = length fish
+  | otherwise =
+    let updatedNested = map (\n -> if n == 0 then [6, 8] else [n - 1]) fish
+        updated = concat updatedNested
+     in e1 (n - 1) updated
+
+update :: Map.Map Int Int -> Int -> Int -> Int
+update hmap 8 _ = hmap ! 0
+update hmap 6 _ = (hmap ! 0) + (hmap ! 7)
+update hmap n _ = hmap ! (n + 1)
+
+e2 :: Int -> Map.Map Int Int -> Int
+e2 n hmap
+  | n == 0 = sum (Map.elems hmap)
+  | otherwise =
+    let newHmap = Map.mapWithKey (update hmap) hmap
+     in e2 (n - 1) newHmap
+
+main :: IO ()
+main =
+  do
+    contents <- getContents
+    let initial = contents $> pack .> split (== ',') .> map (unpack .> read) :: [Int]
+
+    e1 80 initial $> print
+    let hmapInit = Map.fromList [(k, v) | k <- [0 .. 8], v <- [0]]
+    let hmap = foldr (\fish -> Map.insertWith (+) fish 1) hmapInit initial
+    e2 256 hmap $> print