Day 25: Full of Hot Air

ephemient · Dec 25, 2022 · c4a55f9 · c4a55f9
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diff --git a/README.md b/README.md
@@ -30,3 +30,4 @@ Development occurs in language-specific directories:
 |[Day22.hs](hs/src/Day22.hs)|[Day22.kt](kt/src/commonMain/kotlin/com/github/ephemient/aoc2022/Day22.kt)|[day22.py](py/aoc2022/day22.py)|[day22.rs](rs/src/day22.rs)|
 |[Day23.hs](hs/src/Day23.hs)|[Day23.kt](kt/src/commonMain/kotlin/com/github/ephemient/aoc2022/Day23.kt)|[day23.py](py/aoc2022/day23.py)|[day23.rs](rs/src/day23.rs)|
 |[Day24.hs](hs/src/Day24.hs)|[Day24.kt](kt/src/commonMain/kotlin/com/github/ephemient/aoc2022/Day24.kt)|[day24.py](py/aoc2022/day24.py)|[day24.rs](rs/src/day24.rs)|
+|[Day25.hs](hs/src/Day25.hs)|
diff --git a/hs/aoc2022.cabal b/hs/aoc2022.cabal
@@ -35,6 +35,7 @@ data-files:
   , day22.txt
   , day23.txt
   , day24.txt
+  , day25.txt
 
 extra-source-files:
     README.md
@@ -66,6 +67,7 @@ library
       , Day22
       , Day23
       , Day24
+      , Day25
     build-depends:
         array ^>=0.5.4.0
       , base ^>=4.16.0.0
@@ -132,6 +134,7 @@ test-suite aoc2022-test
       , Day22Spec
       , Day23Spec
       , Day24Spec
+      , Day25Spec
     hs-source-dirs:   test
     default-language: GHC2021
     build-tool-depends:

diff --git a/hs/app/Main.hs b/hs/app/Main.hs
@@ -26,6 +26,7 @@ import Day21 (day21a, day21b)
 import Day22 (day22a, day22b)
 import Day23 (day23a, day23b)
 import Day24 (day24a, day24b)
+import Day25 (day25)
 
 import Control.Monad ((<=<), ap, when)
 import Data.Function (on)
@@ -79,3 +80,4 @@ main = do
     run 22 print [day22a, day22b]
     run 23 print [day23a, day23b]
     run 24 (maybe (fail "(⊥)") print) [day24a, day24b]
+    run 25 TIO.putStrLn [day25]
diff --git a/hs/bench/Main.hs b/hs/bench/Main.hs
@@ -29,6 +29,7 @@ import Day21 (day21a, day21b)
 import Day22 (day22a, day22b)
 import Day23 (day23a, day23b)
 import Day24 (day24a, day24b)
+import Day25 (day25)
 import Paths_aoc2022 (getDataFileName)
 import System.Environment.Blank (getEnv, setEnv, unsetEnv)
 
@@ -141,4 +142,7 @@ main = defaultMain
       [ bench "part 1" $ nf day24a input
       , bench "part 2" $ nf day24b input
       ]
+  , env (getDayInput 25) $ \input -> bgroup "Day 24"
+      [ bench "part 1" $ nf day25 input
+      ]
   ]
diff --git a/hs/src/Day25.hs b/hs/src/Day25.hs
@@ -0,0 +1,20 @@
+{-|
+Module:         Day25
+Description:    <https://adventofcode.com/2022/day/25 Day 25: Full of Hot Air>
+-}
+module Day25 (day25) where
+
+import Data.Char (digitToInt, intToDigit)
+import Data.Text (Text)
+import qualified Data.Text as T (foldl', lines, unfoldr, reverse)
+
+day25 :: Text -> Text
+day25 = T.reverse . T.unfoldr g . sum . map (T.foldl' f 0) . T.lines where
+    f k '=' = 5 * k - 2
+    f k '-' = 5 * k - 1
+    f k c = 5 * k + digitToInt c
+    g 0 = Nothing
+    g n = Just $ case n `divMod` 5 of
+        (q, 3) -> ('=', q + 1)
+        (q, 4) -> ('-', q + 1)
+        (q, r) -> (intToDigit r, q)
diff --git a/hs/test/Day25Spec.hs b/hs/test/Day25Spec.hs
@@ -0,0 +1,30 @@
+{-# LANGUAGE OverloadedStrings #-}
+module Day25Spec (spec) where
+
+import Data.Text (Text)
+import qualified Data.Text as T (unlines)
+import Day25 (day25)
+import Test.Hspec (Spec, describe, it, shouldBe)
+
+example :: Text
+example = T.unlines
+  [ "1=-0-2"
+  , "12111"
+  , "2=0="
+  , "21"
+  , "2=01"
+  , "111"
+  , "20012"
+  , "112"
+  , "1=-1="
+  , "1-12"
+  , "12"
+  , "1="
+  , "122"
+  ]
+
+spec :: Spec
+spec = do
+    describe "part 1" $ do
+        it "examples" $ do
+            day25 example `shouldBe` "2=-1=0"