Day 1 + Day 2

.gitignore

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+/dist-newstyle
+/inputs

CHANGELOG.md

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+# Revision history for aoc2024
+
+## 0.1.0.0 -- YYYY-mm-dd
+
+* First version. Released on an unsuspecting world.

LICENSE

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+Copyright (c) 2024, Annwan
+
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of the copyright holder nor the names of its
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

aoc2024.cabal

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+cabal-version:      3.4
+name:               aoc2024
+version:            0.1.0.0
+synopsis:           AOC 2024 solutions
+homepage:           https://git.annwan.me/Annwan/aoc2024
+license:            BSD-3-Clause
+license-file:       LICENSE
+author:             Annwan
+maintainer:         annwan@annwan.me
+build-type:         Simple
+extra-doc-files:    CHANGELOG.md
+common warnings
+    ghc-options: -Wall
+
+library
+    import:           warnings
+    exposed-modules:  Day1, Day2
+    build-depends:    base ^>=4.18.0.0
+    hs-source-dirs:   src
+    default-language: GHC2021
+
+test-suite aoc2024-test
+    import:           warnings
+    default-language: GHC2021
+    type:             exitcode-stdio-1.0
+    hs-source-dirs:   test
+    main-is:          Main.hs
+    build-depends:
+        base ^>=4.18.0.0,
+        aoc2024,
+        hspec,
+        hspec-contrib
+
+executable aoc2024-runner
+    import:           warnings
+    default-language: GHC2021
+    hs-source-dirs:   run
+    main-is:          Main.hs
+    build-depends:
+        base ^>=4.18.0.0,
+        aoc2024,

run/Main.hs

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+module Main where
+import qualified Day1 as D1
+import qualified Day2 as D2
+
+solutions :: [(String -> String, String -> String)]
+solutions = [(D1.part1, D1.part2),
+             (D2.part1, D2.part2)]
+
+
+run :: Int -> Int -> IO () 
+run day part = do
+  input <- readFile ("inputs/" ++ show day)
+  let select = if part == 1 then fst else snd
+  putStrLn $ select (solutions !! (day - 1)) input
+  pure ()
+
+
+main :: IO ()
+main = do
+  day <- getLine
+  problem <- getLine
+  run (read day :: Int) (read problem :: Int)
+  

src/Day1.hs

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+module Day1 (part1, part2) where
+
+import Data.List (transpose, sort)
+
+part1' :: [[Integer]] -> Integer
+part1' [a, b] = sum
+              . map (\(x, y) -> abs (x - y))
+              $ zip (sort a) (sort b)
+part1' _ = error "Unreachable"
+
+part1 :: String -> String
+part1 = show . part1' . prepare
+  where
+    prepare :: String -> [[Integer]]
+    prepare = transpose
+              . map (map read . words)
+              . lines
+
+part2' :: [[Integer]] -> Integer
+part2' [a, b] = sum
+              . zipWith (*) a
+              . map (\x -> count x b)
+              $ a
+  where
+    count :: Eq a => a -> [a] -> Integer
+    count what (x:xs) = count what xs + if what == x then 1 else 0
+    count _ [] = 0
+part2' _ = error "Unreachable"
+
+part2 :: String -> String
+part2 = show . part2'. prepare
+  where
+    prepare :: String -> [[Integer]]
+    prepare = transpose
+              . map (map read . words)
+              . lines

src/Day2.hs

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+module Day2 (part1, part2) where
+import Data.List (subsequences)
+
+isSafe :: [Integer] -> Bool
+isSafe x = isSafeIntevals x && (isAscending x || isDescending x)
+  where
+    isSafeIntevals :: [Integer] -> Bool
+    isSafeIntevals = all (\(a, b) -> 3 >= abs (a - b)) . pairs
+    isAscending :: [Integer] -> Bool
+    isAscending = all (\(a, b) -> a < b) . pairs
+    isDescending :: [Integer] -> Bool
+    isDescending = all (\(a, b) -> a > b) . pairs
+    pairs :: [a] -> [(a, a)]
+    pairs [_] = []
+    pairs [] = []
+    pairs (x1:x2:xs) = (x1, x2) : pairs (x2:xs)
+
+
+
+part1 :: String -> String
+part1 = show
+        . length
+        . filter isSafe
+        . prepare
+  where
+    prepare :: String -> [[Integer]]
+    prepare = map (map read . words)
+              . lines
+    
+    
+part2 :: String -> String
+part2 = show
+        . length
+        . filter (\x ->
+                    isSafe x
+                    || any isSafe [y | y <- subsequences x, length y == length x - 1])
+        . prepare
+  where
+    prepare :: String -> [[Integer]]
+    prepare = map (map read . words) . lines

test/Main.hs

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+module Main (main) where
+import Test.Hspec
+import Day1
+import Day2
+
+main :: IO ()
+main = hspec $ do
+  describe "Day1" $ do
+    it "solves part 1" $ do
+      Day1.part1 "3   4\n4   3\n2   5\n1   3\n3   9\n3   3\n" `shouldBe` "11"
+    it "solves part 2" $ do
+      Day1.part2 "3   4\n4   3\n2   5\n1   3\n3   9\n3   3\n" `shouldBe` "31"
+  describe "Day 2" $ do
+    it "solves part 1" $ do
+      Day2.part1 "7 6 4 2 1\n1 2 7 8 9\n9 7 6 2 1\n1 3 2 4 5\n8 6 4 4 1\n1 3 6 7 9" `shouldBe` "2"
+    it "solves part 2" $ do
+      Day2.part2 "7 6 4 2 1\n1 2 7 8 9\n9 7 6 2 1\n1 3 2 4 5\n8 6 4 4 1\n1 3 6 7 9" `shouldBe` "4"