haskell: 2023 15 a

2023/haskell/aoc2023.cabal

@@ -28,6 +28,7 @@ library
     Day08
     Day09
     Day10
+    Day15
 
   other-modules:
     Misc

2023/haskell/app/Main.hs

@@ -11,7 +11,8 @@ import Utils (readInput)
 --import qualified Day07
 --import qualified Day08
 --import qualified Day09
-import qualified Day10
+--import qualified Day10
+import qualified Day15
 
 
 run :: (Show b, Show c)
@@ -40,4 +41,5 @@ main = do
   --run 07 Day07.parse Day07.solveA Day07.solveB
   --run 08 Day08.parse Day08.solveA Day08.solveB
   --run 09 Day09.parse Day09.solveA Day09.solveB
-  run 10 Day10.parse Day10.solveA Day10.solveB
+  --run 10 Day10.parse Day10.solveA Day10.solveB
+  run 15 Day15.parse Day15.solveA Day15.solveA

2023/haskell/solutions/Day15.hs

@@ -0,0 +1,29 @@
+{-# LANGUAGE OverloadedStrings #-}
+module Day15 (parse, solveA) where
+
+import Data.Text (Text)
+import qualified Data.Text as T
+import Data.Char (ord, isSpace)
+
+
+input :: Text
+input = "rn=1,cm-,qp=3,cm=2,qp-,pc=4,ot=9,ab=5,pc-,pc=6,ot=7"
+
+
+parse :: Text -> Either String [Text]
+parse = Right . T.splitOn "," . T.filter (not . isSpace)
+
+hash :: Text -> Int
+hash = foldl step 0 . T.unpack
+  where
+    step :: Int -> Char -> Int
+    step curr = (`rem` 256) . (17 *) . (curr +) . ord
+
+solveA :: [Text] -> Int
+solveA = sum . map hash
+
+
+
+-- >>> solveA <$> parse input
+-- Right 1320
+

2023/haskell/tests/Main.hs

@@ -13,6 +13,7 @@ import qualified Day07
 import qualified Day08
 import qualified Day09
 import qualified Day10
+import qualified Day15
 
 
 day01 :: Test
@@ -275,6 +276,18 @@ day10 =
       \L.L7LFJ|||||FJL7||LJ\n\
       \L7JLJL-JLJLJL--JLJ.L\n"
 
+day15 :: Test
+day15 =
+  let parsedA1 = Day15.parse inputA1
+      parsedA2 = Day15.parse inputA2
+  in TestList
+    [ TestCase $ assertEqual "A" (Right 52)    (Day15.solveA <$> parsedA1)
+    , TestCase $ assertEqual "A" (Right 1320)  (Day15.solveA <$> parsedA2)
+    ]
+  where
+    inputA1 = "HASH"
+    inputA2 = "rn=1,cm-,qp=3,cm=2,qp-,pc=4,ot=9,ab=5,pc-,pc=6,ot=7"
+
 tests :: Test
 tests = TestList
   [ TestLabel "01" day01
@@ -287,6 +300,7 @@ tests = TestList
   , TestLabel "08" day08
   , TestLabel "09" day09
   , TestLabel "10" day10
+  , TestLabel "15" day15
   ]
 
 main :: IO ()