aboutsummaryrefslogtreecommitdiff
path: root/2023/06-Wait_For_It
diff options
context:
space:
mode:
authorJulien Dessaux2023-12-06 18:57:13 +0100
committerJulien Dessaux2023-12-06 18:57:13 +0100
commite1537be332c301014d81f3abee9c84a9b231cc24 (patch)
tree2f2247deaed414288e1f74f143b25311b12437d8 /2023/06-Wait_For_It
parent2023-05 in haskell (diff)
downloadadvent-of-code-e1537be332c301014d81f3abee9c84a9b231cc24.tar.gz
advent-of-code-e1537be332c301014d81f3abee9c84a9b231cc24.tar.bz2
advent-of-code-e1537be332c301014d81f3abee9c84a9b231cc24.zip
2023-06 in haskell
Diffstat (limited to '')
-rw-r--r--2023/06-Wait_For_It/example2
-rw-r--r--2023/06-Wait_For_It/first.hs55
-rw-r--r--2023/06-Wait_For_It/input2
-rw-r--r--2023/06-Wait_For_It/second.hs55
4 files changed, 114 insertions, 0 deletions
diff --git a/2023/06-Wait_For_It/example b/2023/06-Wait_For_It/example
new file mode 100644
index 0000000..28f5ae9
--- /dev/null
+++ b/2023/06-Wait_For_It/example
@@ -0,0 +1,2 @@
+Time: 7 15 30
+Distance: 9 40 200
diff --git a/2023/06-Wait_For_It/first.hs b/2023/06-Wait_For_It/first.hs
new file mode 100644
index 0000000..36e24be
--- /dev/null
+++ b/2023/06-Wait_For_It/first.hs
@@ -0,0 +1,55 @@
+-- requires cabal install --lib megaparsec parser-combinators
+module Main (main) where
+
+import Control.Applicative.Permutations
+import Control.Monad (void, when)
+import Data.Char qualified as C
+import Data.Either
+import Data.List qualified as L
+import Data.Map qualified as M
+import Data.Maybe
+import Data.Set qualified as S
+import Data.Void (Void)
+import Text.Megaparsec
+import Text.Megaparsec.Char
+
+import Debug.Trace
+
+exampleExpectedOutput = 288
+
+data Input = Input [Int] [Int] deriving Show -- time distance
+
+type Parser = Parsec Void String
+
+parseNumber :: Parser Int
+parseNumber = read <$> some digitChar <* many (char ' ')
+
+parseInput' :: Parser Input
+parseInput' = Input <$> (string "Time:" *> many (char ' ') *> some parseNumber <* eol)
+ <*> (string "Distance:" *> many (char ' ') *> some parseNumber <* eol <* eof)
+
+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'
+
+race :: Int -> Int -> Int
+race limit record = limit + 1 - 2 * threshold
+ where
+ threshold = minTimeToBeat 0
+ minTimeToBeat :: Int -> Int
+ minTimeToBeat t | (limit - t) * t > record = t
+ | otherwise = minTimeToBeat (t+1)
+
+compute :: Input -> Int
+compute (Input times distances) = product $ zipWith race times distances
+
+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/2023/06-Wait_For_It/input b/2023/06-Wait_For_It/input
new file mode 100644
index 0000000..f0fce7b
--- /dev/null
+++ b/2023/06-Wait_For_It/input
@@ -0,0 +1,2 @@
+Time: 46 85 75 82
+Distance: 208 1412 1257 1410
diff --git a/2023/06-Wait_For_It/second.hs b/2023/06-Wait_For_It/second.hs
new file mode 100644
index 0000000..489af0c
--- /dev/null
+++ b/2023/06-Wait_For_It/second.hs
@@ -0,0 +1,55 @@
+-- requires cabal install --lib megaparsec parser-combinators
+module Main (main) where
+
+import Control.Applicative.Permutations
+import Control.Monad (void, when)
+import Data.Char qualified as C
+import Data.Either
+import Data.List qualified as L
+import Data.Map qualified as M
+import Data.Maybe
+import Data.Set qualified as S
+import Data.Void (Void)
+import Text.Megaparsec
+import Text.Megaparsec.Char
+
+import Debug.Trace
+
+exampleExpectedOutput = 71503
+
+data Input = Input [Int] [Int] deriving Show -- time distance
+
+type Parser = Parsec Void String
+
+parseNumber :: Parser Int
+parseNumber = read <$> some (digitChar <* many (char ' '))
+
+parseInput' :: Parser Input
+parseInput' = Input <$> (string "Time:" *> many (char ' ') *> some parseNumber <* eol)
+ <*> (string "Distance:" *> many (char ' ') *> some parseNumber <* eol <* eof)
+
+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'
+
+race :: Int -> Int -> Int
+race limit record = limit + 1 - 2 * threshold
+ where
+ threshold = minTimeToBeat 0
+ minTimeToBeat :: Int -> Int
+ minTimeToBeat t | (limit - t) * t > record = t
+ | otherwise = minTimeToBeat (t+1)
+
+compute :: Input -> Int
+compute (Input times distances) = product $ zipWith race times distances
+
+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