From ca9b64a8e608093acdd1d8e321c6bde3c26ba9b3 Mon Sep 17 00:00:00 2001
From: Daniele Fucini <dfucini@gmail.com>
Date: Sun, 22 Dec 2024 09:52:47 +0100
Subject: [PATCH] Day 22, Part 1

---
 adventofcode2024.cabal |  1 +
 src/Day22.hs           | 17 +++++++++++++++++
 src/Main.hs            |  6 ++++--
 3 files changed, 22 insertions(+), 2 deletions(-)
 create mode 100644 src/Day22.hs

diff --git a/adventofcode2024.cabal b/adventofcode2024.cabal
index 2a5684d..0ae47bb 100644
--- a/adventofcode2024.cabal
+++ b/adventofcode2024.cabal
@@ -56,4 +56,5 @@ executable adventofcode2024
     Day17
     Day18
     Day19
+    Day22
     Graph
diff --git a/src/Day22.hs b/src/Day22.hs
new file mode 100644
index 0000000..8c44a9c
--- /dev/null
+++ b/src/Day22.hs
@@ -0,0 +1,17 @@
+module Day22 (day22_1) where
+
+import Data.Bits
+
+getSecretNumber :: Integer -> Int -> Integer
+getSecretNumber x 0 = x
+getSecretNumber x n =
+  let x' = ((x `shiftL` 6) `xor` x) `mod` 16777216
+      x'' = ((x' `shiftR` 5) `xor` x') `mod` 16777216
+   in getSecretNumber (((x'' `shiftL` 11) `xor` x'') `mod` 16777216) (n - 1)
+
+day22_1 :: IO ()
+day22_1 = do
+  contents <- map read . lines <$> readFile "input/day22.txt"
+  putStrLn $
+    "Day 22, Puzzle 1 solution: "
+      ++ show (sum $ map (`getSecretNumber` 2000) contents)
diff --git a/src/Main.hs b/src/Main.hs
index 6047577..b314b39 100644
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -18,6 +18,7 @@ import Day15 (day15_1)
 import Day17 (day17_1, day17_2)
 import Day18 (day18_1, day18_2)
 import Day19 (day19_1)
+import Day22 (day22_1)
 import System.Environment (getArgs)
 
 main :: IO ()
@@ -94,12 +95,13 @@ main = do
     "17" : "1" : _ -> day17_1
     "17" : "2" : _ -> day17_2
     "17" : _ -> do
-        day17_1
-        day17_2
+      day17_1
+      day17_2
     "18" : "1" : _ -> day18_1
     "18" : "2" : _ -> day18_2
     "18" : _ -> do
       day18_1
       day18_2
     "19" : "1" : _ -> day19_1
+    "22" : "1" : _ -> day22_1
     _ -> error "Not implemented"