Add Day 6 solutions

README.md

@@ -7,4 +7,4 @@
 |03 |★ ★  |09 |     |
 |04 |★ ★  |10 |     |
 |05 |★ ★  |11 |     |
-|06 |     |12 |     |
+|06 |★ ★  |12 |     |

adventofcode2025.cabal

@@ -35,3 +35,4 @@ executable adventofcode2025
     Day03
     Day04
     Day05
+    Day06

src/Day06.hs

@@ -0,0 +1,53 @@
+module Day06
+  ( day06_1,
+    day06_2,
+  )
+where
+
+import Data.List (groupBy, transpose)
+
+solveProblem :: [String] -> Int
+solveProblem problem =
+  let op = last problem
+      values = map read $ init problem
+   in case op of
+        "+" -> sum values
+        "*" -> product values
+        _ -> 0
+
+solveProblem' :: [String] -> Int
+solveProblem' [] = 0
+solveProblem' (x : xs) =
+  let op = last x
+      v1 = read $ init x
+      values = v1 : [read v | v <- xs]
+   in case op of
+        '+' -> sum values
+        '*' -> product values
+        _ -> 0
+
+parseInput :: IO [[String]]
+parseInput = do
+  transpose . map words . lines <$> readFile "input/day6.txt"
+
+parseInput' :: IO [[String]]
+parseInput' = do
+  input <- transpose . lines <$> readFile "input/day6.txt"
+  let problems = map (filter (not . all (== ' '))) $ groupBy (\_ y -> not (all (== ' ') y)) input
+  return problems
+
+day06_1 :: IO ()
+day06_1 = do
+  input <- parseInput
+  let result = sum $ map solveProblem input
+  putStrLn $
+    "Day 6, Puzzle 1 solution: "
+      ++ show result
+
+day06_2 :: IO ()
+day06_2 = do
+  input <- parseInput'
+  let result = sum $ map solveProblem' input
+  putStrLn $
+    "Day 6, Puzzle 2 solution: "
+      ++ show result

src/Main.hs

@@ -5,6 +5,7 @@ import Day02 (day02_1, day02_2)
 import Day03 (day03_1, day03_2)
 import Day04 (day04_1, day04_2)
 import Day05 (day05_1, day05_2)
+import Day06 (day06_1, day06_2)
 import System.Environment (getArgs)
 
 main :: IO ()
@@ -36,6 +37,11 @@ main = do
     "5" : _ -> do
       day05_1
       day05_2
+    "6" : "1" : _ -> day06_1
+    "6" : "2" : _ -> day06_2
+    "6" : _ -> do
+      day06_1
+      day06_2
     "all" : _ -> do
       day01_1
       day01_2
@@ -47,4 +53,6 @@ main = do
       day04_2
       day05_1
       day05_2
+      day06_1
+      day06_2
     _ -> error "Not implemented"