use Integer -> String -> String for solve

2022/app/Main.hs

@@ -21,5 +21,5 @@ main = do
                       4 -> Aoc.Day4.solve
                       _ -> error "unknown day"
 
-  putStrLn $ show $ f part contents
+  putStrLn $ f part contents
 

2022/src/Aoc/Day1.hs

@@ -19,6 +19,7 @@ part2 = sum . take 3 . sortDesc . inputSums
   where
     sortDesc = sortBy (comparing Down)
 
-solve :: Integer -> String -> Integer
-solve 1 input = part1 input
-solve 2 input = part2 input
+solve :: Integer -> String -> String
+solve 1 input = show $ part1 input
+solve 2 input = show $ part2 input
+solve _ _ = "?"

2022/src/Aoc/Day2.hs

@@ -19,8 +19,8 @@ scoreGame _          = 0
 totalScore :: [[String]] -> Integer
 totalScore = sum . map scoreGame
 
-solve :: Integer -> String -> Integer
-solve 1 input = totalScore games
+solve :: Integer -> String -> String
+solve 1 input = show $ totalScore games
   where
     games = map convertGuide $ parseInput input
 
@@ -29,7 +29,7 @@ solve 1 input = totalScore games
     convertGuide [p, "Z"] = [p, "C"]
     convertGuide xs       = xs
 
-solve 2 input = totalScore games
+solve 2 input = show $ totalScore games
   where
     games = map solveGuide $ parseInput input
 
@@ -45,4 +45,4 @@ solve 2 input = totalScore games
     solveGuide ["C", "Z"] = ["C", "A"]
     solveGuide xs         = xs
 
-solve _ _ = 0
+solve _ _ = "?"

2022/src/Aoc/Day3.hs

@@ -21,9 +21,9 @@ charToInt c
   | 'A' <= c && c <= 'Z' = ord c - ord 'A' + 27
   | otherwise            = -1
 
-solve :: Integer -> String -> Integer
-solve 1 input = sum $ map (toInteger . charToInt . head . shared . halve) $ lines input
+solve :: Integer -> String -> String
+solve 1 input = show $ sum $ map (toInteger . charToInt . head . shared . halve) $ lines input
 
-solve 2 input = sum $ map (toInteger . charToInt . head . shared) $ chunksOf 3 $ lines input
+solve 2 input = show $ sum $ map (toInteger . charToInt . head . shared) $ chunksOf 3 $ lines input
 
-solve _ _ = 0
+solve _ _ = "?"

2022/src/Aoc/Day4.hs

@@ -45,8 +45,8 @@ overlap ((a, b), (c, d))
 solve' :: String -> (Row -> Bool) -> Integer
 solve' input predicate = fromIntegral $ length $ filter predicate $ parse input
 
-solve :: Integer -> String -> Integer
-solve 1 input = solve' input fullOverlap
-solve 2 input = solve' input overlap
+solve :: Integer -> String -> String
+solve 1 input = show $ solve' input fullOverlap
+solve 2 input = show $ solve' input overlap
 
-solve _ _ = 0
+solve _ _ = "?"