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authorJulien Dessaux2024-12-10 09:27:43 +0100
committerJulien Dessaux2024-12-10 09:27:43 +0100
commitf8251081772e217ad537937cd48bb7e3f0541974 (patch)
tree4ab6a0c958898b2662f971f5c53a924f6024e2c0
parent2024-09 in haskell (diff)
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2024-10 in haskell
-rw-r--r--2024/10-Hoof_It/example8
-rw-r--r--2024/10-Hoof_It/first.hs64
-rw-r--r--2024/10-Hoof_It/input40
-rw-r--r--2024/10-Hoof_It/second.hs63
4 files changed, 175 insertions, 0 deletions
diff --git a/2024/10-Hoof_It/example b/2024/10-Hoof_It/example
new file mode 100644
index 0000000..cada9b3
--- /dev/null
+++ b/2024/10-Hoof_It/example
@@ -0,0 +1,8 @@
+89010123
+78121874
+87430965
+96549874
+45678903
+32019012
+01329801
+10456732
diff --git a/2024/10-Hoof_It/first.hs b/2024/10-Hoof_It/first.hs
new file mode 100644
index 0000000..878a30a
--- /dev/null
+++ b/2024/10-Hoof_It/first.hs
@@ -0,0 +1,64 @@
+-- requires cabal install --lib megaparsec parser-combinators heap vector
+module Main (main) where
+
+import Control.Monad (void, when)
+import qualified Data.Set as S
+import qualified Data.Vector as V
+import qualified Data.Vector.Unboxed as VU
+import Data.Void (Void)
+import Text.Megaparsec
+import Text.Megaparsec.Char
+
+exampleExpectedOutput = 36
+
+type Line = VU.Vector Int
+type Input = V.Vector Line
+
+type Parser = Parsec Void String
+
+parseNumber :: Parser Int
+parseNumber = read . pure <$> digitChar
+
+parseLine :: Parser Line
+parseLine = do
+ line <- some parseNumber <* eol
+ return $ VU.generate (length line) (line !!)
+
+parseInput' :: Parser Input
+parseInput' = do
+ line <- some parseLine <* eof
+ return $ V.generate (length line) (line !!)
+
+parseInput :: String -> IO Input
+parseInput filename = do
+ input <- readFile filename
+ case runParser parseInput' filename input of
+ Left bundle -> error $ errorBundlePretty bundle
+ Right input' -> return input'
+
+compute :: Input -> Int
+compute input = sum $ V.imap scoreLine input
+ where
+ scoreLine :: Int -> VU.Vector Int -> Int
+ scoreLine y line = VU.sum $ VU.imap (\x c -> score x y c) line
+ score :: Int -> Int -> Int -> Int
+ score x y c | c == 0 = S.size $ reachableSummits 0 (x, y)
+ | otherwise = 0
+ reachableSummits :: Int -> (Int, Int) -> S.Set (Int, Int)
+ reachableSummits h (x, y) | h == 9 = S.singleton (x, y)
+ | otherwise = S.unions $ map (reachableSummits (h+1)) succ
+ where
+ succ = filter valid [(x-1, y), (x+1, y), (x, y-1), (x, y+1)]
+ valid (x, y) = case input V.!? y of
+ Just line -> case line VU.!? x of
+ Just h' -> h+1 == h'
+ _ -> False
+ _ -> False
+
+main :: IO ()
+main = do
+ example <- parseInput "example"
+ let exampleOutput = compute example
+ when (exampleOutput /= exampleExpectedOutput) (error $ "example failed: got " ++ show exampleOutput ++ " instead of " ++ show exampleExpectedOutput)
+ input <- parseInput "input"
+ print $ compute input
diff --git a/2024/10-Hoof_It/input b/2024/10-Hoof_It/input
new file mode 100644
index 0000000..800a18c
--- /dev/null
+++ b/2024/10-Hoof_It/input
@@ -0,0 +1,40 @@
+1098921121187650126589432104301010017898
+2347810030090543237676546765218921326323
+3256723345121789078545345896237635495410
+0189654656230650129454210910146546786898
+1018706787649843212323407893056544576781
+0123215498556764501012216324567033675410
+1054912389440189650983345413498122189323
+2367804322339218761874214102439232075014
+3494565011878307010965302101521001456985
+4583876910965498123434456517617652327876
+9672978894328767894525467898908543410434
+8701569765419456987616321010119654306523
+7616054100300345865407890121236701217810
+4567123231201210870301456290547896332912
+3258834998303456961210387787678987441003
+4109985867214327898341295689432196556764
+3457876754321016987654254776501001105895
+2568965698130123216510163897567232234996
+1077654147010154105425672198498143497887
+2089503056923269012334789010398056786546
+1123412147874678901109011001267049805430
+0109892130965165210278921123452121012321
+1236783021089014321367630038983430328901
+0345634569870156752456541127604589437610
+1267825478763247843898430934510678576523
+3216910089654130956707321874321987689430
+4505432198703021013210012365899654238321
+3699801789012982787309898456718723148980
+2789789678101276896456721032100210057671
+1008650521010345785454434549321321060362
+2210541430121289890365410678732639871250
+4341232510537656701274320521548747898341
+1056341423498545432789201230699656743432
+2967650345567230101687112345788745234569
+3878981236750121211096001296787230199678
+4589870109889032349125410187590123288767
+5679665010976541498934231095691054177678
+3038754129889650587432145654782567065549
+2125603236778765676501098723123478450030
+3034512345654656565410181010010989321121
diff --git a/2024/10-Hoof_It/second.hs b/2024/10-Hoof_It/second.hs
new file mode 100644
index 0000000..91cff42
--- /dev/null
+++ b/2024/10-Hoof_It/second.hs
@@ -0,0 +1,63 @@
+-- requires cabal install --lib megaparsec parser-combinators heap vector
+module Main (main) where
+
+import Control.Monad (void, when)
+import qualified Data.Vector as V
+import qualified Data.Vector.Unboxed as VU
+import Data.Void (Void)
+import Text.Megaparsec
+import Text.Megaparsec.Char
+
+exampleExpectedOutput = 81
+
+type Line = VU.Vector Int
+type Input = V.Vector Line
+
+type Parser = Parsec Void String
+
+parseNumber :: Parser Int
+parseNumber = read . pure <$> digitChar
+
+parseLine :: Parser Line
+parseLine = do
+ line <- some parseNumber <* eol
+ return $ VU.generate (length line) (line !!)
+
+parseInput' :: Parser Input
+parseInput' = do
+ line <- some parseLine <* eof
+ return $ V.generate (length line) (line !!)
+
+parseInput :: String -> IO Input
+parseInput filename = do
+ input <- readFile filename
+ case runParser parseInput' filename input of
+ Left bundle -> error $ errorBundlePretty bundle
+ Right input' -> return input'
+
+compute :: Input -> Int
+compute input = sum $ V.imap scoreLine input
+ where
+ scoreLine :: Int -> VU.Vector Int -> Int
+ scoreLine y line = VU.sum $ VU.imap (\x c -> score x y c) line
+ score :: Int -> Int -> Int -> Int
+ score x y c | c == 0 = length $ reachableSummits 0 (x, y)
+ | otherwise = 0
+ reachableSummits :: Int -> (Int, Int) -> [(Int, Int)]
+ reachableSummits h (x, y) | h == 9 = [(x, y)]
+ | otherwise = concatMap (reachableSummits (h+1)) succ
+ where
+ succ = filter valid [(x-1, y), (x+1, y), (x, y-1), (x, y+1)]
+ valid (x, y) = case input V.!? y of
+ Just line -> case line VU.!? x of
+ Just h' -> h+1 == h'
+ _ -> False
+ _ -> False
+
+main :: IO ()
+main = do
+ example <- parseInput "example"
+ let exampleOutput = compute example
+ when (exampleOutput /= exampleExpectedOutput) (error $ "example failed: got " ++ show exampleOutput ++ " instead of " ++ show exampleExpectedOutput)
+ input <- parseInput "input"
+ print $ compute input