From fc4939c7f851f90e1378e47733b5011a3d962bf1 Mon Sep 17 00:00:00 2001
From: Daniele Fucini <dfucini@gmail.com>
Date: Tue, 17 Dec 2024 23:27:09 +0100
Subject: [PATCH] Day 17, Part 1

---
 adventofcode2024.cabal |   2 +
 src/Day17/Puzzle1.hs   | 125 +++++++++++++++++++++++++++++++++++++++++
 src/Main.hs            |   2 +
 3 files changed, 129 insertions(+)
 create mode 100644 src/Day17/Puzzle1.hs

diff --git a/adventofcode2024.cabal b/adventofcode2024.cabal
index 5db34e5..1cf919a 100644
--- a/adventofcode2024.cabal
+++ b/adventofcode2024.cabal
@@ -23,6 +23,7 @@ executable adventofcode2024
                      , containers
                      , regex-tdfa
                      , matrix
+                     , mtl
   ghc-options:         -Wall
                        -Wcompat
                        -Widentities
@@ -60,3 +61,4 @@ executable adventofcode2024
     Day14.Puzzle1
     Day14.Puzzle2
     Day15.Puzzle1
+    Day17.Puzzle1
diff --git a/src/Day17/Puzzle1.hs b/src/Day17/Puzzle1.hs
new file mode 100644
index 0000000..25f475e
--- /dev/null
+++ b/src/Day17/Puzzle1.hs
@@ -0,0 +1,125 @@
+{-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}
+
+module Day17.Puzzle1 (day17_1) where
+
+import Control.Monad.State
+import Data.Bits
+import Data.Char (isDigit)
+import Data.List (uncons)
+import Data.List.Split (splitOn)
+import Data.Maybe (fromJust)
+
+type Program = [Int]
+
+data Computer = Computer
+  { registerA :: Integer,
+    registerB :: Integer,
+    registerC :: Integer,
+    program :: Program,
+    pointer :: Int,
+    output :: String
+  }
+  deriving (Show)
+
+adv :: Int -> State Computer ()
+adv n = state $ \c ->
+  if n `elem` [0 .. 3]
+    then ((), c {registerA = registerA c `div` (2 ^ n), pointer = pointer c + 2})
+    else
+      if n == 4
+        then ((), c {registerA = registerA c `div` (2 ^ registerA c), pointer = pointer c + 2})
+        else
+          if n == 5
+            then ((), c {registerA = registerA c `div` (2 ^ registerB c), pointer = pointer c + 2})
+            else ((), c {registerA = registerA c `div` (2 ^ registerC c), pointer = pointer c + 2})
+
+bxl :: Int -> State Computer ()
+bxl n = state $ \c -> ((), c {registerB = registerB c `xor` fromIntegral n, pointer = pointer c + 2})
+
+bst :: Int -> State Computer ()
+bst n = state $ \c ->
+  if n `elem` [0 .. 3]
+    then ((), c {registerB = fromIntegral n `mod` 8, pointer = pointer c + 2})
+    else
+      if n == 4
+        then ((), c {registerB = registerA c `mod` 8, pointer = pointer c + 2})
+        else
+          if n == 5
+            then ((), c {registerB = registerB c `mod` 8, pointer = pointer c + 2})
+            else ((), c {registerB = registerC c `mod` 8, pointer = pointer c + 2})
+
+jnz :: Int -> State Computer ()
+jnz n = state $ \c ->
+  if registerA c == 0
+    then ((), c {pointer = pointer c + 2})
+    else ((), c {pointer = n})
+
+bxc :: State Computer ()
+bxc = state $ \c -> ((), c {registerB = registerB c `xor` registerC c, pointer = pointer c + 2})
+
+out :: Int -> State Computer ()
+out n = state $ \c ->
+  if n `elem` [0 .. 3]
+    then ((), c {output = output c ++ "," ++ show (n `mod` 8), pointer = pointer c + 2})
+    else
+      if n == 4
+        then ((), c {output = output c ++ "," ++ show (registerA c `mod` 8), pointer = pointer c + 2})
+        else
+          if n == 5
+            then ((), c {output = output c ++ "," ++ show (registerB c `mod` 8), pointer = pointer c + 2})
+            else ((), c {output = output c ++ "," ++ show (registerC c `mod` 8), pointer = pointer c + 2})
+
+bdv :: Int -> State Computer ()
+bdv n = state $ \c ->
+  if n `elem` [0 .. 3]
+    then ((), c {registerB = registerA c `div` (2 ^ n), pointer = pointer c + 2})
+    else
+      if n == 4
+        then ((), c {registerB = registerA c `div` (2 ^ registerA c), pointer = pointer c + 2})
+        else
+          if n == 5
+            then ((), c {registerB = registerA c `div` (2 ^ registerB c), pointer = pointer c + 2})
+            else ((), c {registerB = registerA c `div` (2 ^ registerC c), pointer = pointer c + 2})
+
+cdv :: Int -> State Computer ()
+cdv n = state $ \c ->
+  if n `elem` [0 .. 3]
+    then ((), c {registerC = registerA c `div` (2 ^ n), pointer = pointer c + 2})
+    else
+      if n == 4
+        then ((), c {registerC = registerA c `div` (2 ^ registerA c), pointer = pointer c + 2})
+        else
+          if n == 5
+            then ((), c {registerC = registerA c `div` (2 ^ registerB c), pointer = pointer c + 2})
+            else ((), c {registerC = registerA c `div` (2 ^ registerC c), pointer = pointer c + 2})
+
+getInstruction :: State Computer (Int, Int)
+getInstruction = state $ \c -> ((program c !! pointer c, program c !! (pointer c + 1)), c)
+
+runProgram :: State Computer ()
+runProgram = do
+  c <- get
+  if pointer c >= length (program c)
+    then return ()
+    else do
+      (ins, op) <- getInstruction
+      case ins of
+        0 -> adv op
+        1 -> bxl op
+        2 -> bst op
+        3 -> jnz op
+        4 -> bxc
+        5 -> out op
+        6 -> bdv op
+        7 -> cdv op
+        _ -> return ()
+      runProgram
+
+day17_1 :: IO ()
+day17_1 = do
+  contents <- lines <$> readFile "input/day17.txt"
+  let [r, [p]] = splitOn [""] contents
+      registers = map (read . filter isDigit) r
+      prog = map (read . filter isDigit) $ splitOn "," p
+      computer = Computer {registerA = fst . fromJust $ uncons registers, registerB = registers !! 1, registerC = registers !! 2, pointer = 0, program = prog, output = ""}
+  print . drop 1 . output $ execState runProgram computer
diff --git a/src/Main.hs b/src/Main.hs
index 0a325b1..9686155 100644
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -27,6 +27,7 @@ import Day13.Puzzle2
 import Day14.Puzzle1
 import Day14.Puzzle2
 import Day15.Puzzle1
+import Day17.Puzzle1
 import System.Environment (getArgs)
 
 main :: IO ()
@@ -60,4 +61,5 @@ main = do
     "14" : "1" : _ -> day14_1
     "14" : "2" : _ -> day14_2
     "15" : "1" : _ -> day15_1
+    "17" : "1" : _ -> day17_1
     _ -> error "Not implemented"