From 4c620530e2a25f8d372f0f4357b917f78517879d Mon Sep 17 00:00:00 2001
From: Jan Tuomi <jans.tuomi@gmail.com>
Date: Wed, 8 Dec 2021 16:19:21 +0200
Subject: Day 06

---
 day06/input.txt |  1 +
 day06/main.hs   | 37 +++++++++++++++++++++++++++++++++++++
 day06/test.txt  |  1 +
 3 files changed, 39 insertions(+)
 create mode 100644 day06/input.txt
 create mode 100644 day06/main.hs
 create mode 100644 day06/test.txt

diff --git a/day06/input.txt b/day06/input.txt
new file mode 100644
index 0000000..715ea56
--- /dev/null
+++ b/day06/input.txt
@@ -0,0 +1 @@
+1,4,1,1,1,1,1,1,1,4,3,1,1,3,5,1,5,3,2,1,1,2,3,1,1,5,3,1,5,1,1,2,1,2,1,1,3,1,5,1,1,1,3,1,1,1,1,1,1,4,5,3,1,1,1,1,1,1,2,1,1,1,1,4,4,4,1,1,1,1,5,1,2,4,1,1,4,1,2,1,1,1,2,1,5,1,1,1,3,4,1,1,1,3,2,1,1,1,4,1,1,1,5,1,1,4,1,1,2,1,4,1,1,1,3,1,1,1,1,1,3,1,3,1,1,2,1,4,1,1,1,1,3,1,1,1,1,1,1,2,1,3,1,1,1,1,4,1,1,1,1,1,1,1,1,1,1,1,1,2,1,1,5,1,1,1,2,2,1,1,3,5,1,1,1,1,3,1,3,3,1,1,1,1,3,5,2,1,1,1,1,5,1,1,1,1,1,1,1,2,1,2,1,1,1,2,1,1,1,1,1,2,1,1,1,1,1,5,1,4,3,3,1,3,4,1,1,1,1,1,1,1,1,1,1,4,3,5,1,1,1,1,1,1,1,1,1,1,1,1,1,5,2,1,4,1,1,1,1,1,1,1,1,1,1,1,1,1,5,1,1,1,1,1,1,1,1,2,1,4,4,1,1,1,1,1,1,1,5,1,1,2,5,1,1,4,1,3,1,1
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
diff --git a/day06/test.txt b/day06/test.txt
new file mode 100644
index 0000000..55129f1
--- /dev/null
+++ b/day06/test.txt
@@ -0,0 +1 @@
+3,4,3,1,2
-- 
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