Day 06

advent-of-code2023.cabal

@@ -25,12 +25,14 @@ library
       Solutions.Day03
       Solutions.Day04
       Solutions.Day05
+      Solutions.Day06
   other-modules:
       Lib.AOC
       Lib.List
       Lib.Matrix
       Lib.Parsing
       Main
+      Solutions.DayX
       Paths_advent_of_code2023
   autogen-modules:
       Paths_advent_of_code2023
@@ -83,6 +85,8 @@ executable advent-of-code2023
       Solutions.Day03
       Solutions.Day04
       Solutions.Day05
+      Solutions.Day06
+      Solutions.DayX
       Paths_advent_of_code2023
   autogen-modules:
       Paths_advent_of_code2023
@@ -132,6 +136,7 @@ test-suite unit-test
       Day03
       Day04
       Day05
+      Day06
       Paths_advent_of_code2023
   autogen-modules:
       Paths_advent_of_code2023

data/day06.txt

@@ -0,0 +1,2 @@
+Time:        46     68     98     66
+Distance:   358   1054   1807   1080

package.yaml

@@ -70,6 +70,7 @@ library:
     - Solutions.Day03
     - Solutions.Day04
     - Solutions.Day05
+    - Solutions.Day06
 
 tests:
   unit-test:

src/Main.hs

@@ -4,6 +4,7 @@ import Solutions.Day02 (day02)
 import Solutions.Day03 (day03)
 import Solutions.Day04 (day04)
 import Solutions.Day05 (day05)
+import Solutions.Day06 (day06)
 
 main :: IO ()
 main = do
@@ -12,3 +13,4 @@ main = do
   day03
   day04
   day05
+  day06

src/Solutions/Day06.hs

@@ -0,0 +1,28 @@
+module Solutions.Day06 (day06, parser, part1, part2) where
+
+import Lib.AOC (runSolution)
+import Data.Foldable (Foldable(foldl'))
+
+type Input = [(Int, Int)]
+
+parser :: String -> Input
+parser = (\[l1,l2] -> zip l1 l2) . map (map read . drop 1 . words) . lines
+
+generateHistogram :: Int -> [Int]
+generateHistogram time = map (\x -> x * (time - x)) [0 .. time]
+
+numOfWinningOptions :: (Int, Int) -> Int
+numOfWinningOptions (time, recordDistance) = length $ filter (> recordDistance) (generateHistogram time)
+
+part1 :: Input -> Int
+part1 = product . map numOfWinningOptions
+
+part2 :: Input -> Int
+part2 input = numOfWinningOptions $ fixInput input
+  where
+    combineNumbers n1 n2 = read (show n1 ++ show n2)
+
+    fixInput = foldl' (\(totalT, totalD) (t, d) -> (combineNumbers totalT t, combineNumbers totalD d)) (0, 0)
+
+day06 :: IO ()
+day06 = runSolution "06" parser part1 part2

src/Solutions/DayX.hs

@@ -0,0 +1,17 @@
+module Solutions.DayX (dayX, parser, part1, part2) where
+
+import Lib.AOC (runSolution)
+
+type Input = String
+
+parser :: String -> Input
+parser = id
+
+part1 :: Input -> String
+part1 = id
+
+part2 :: Input -> String
+part2 = id
+
+dayX :: IO ()
+dayX = runSolution "X" parser part1 part2

test/Day06.hs

@@ -0,0 +1,32 @@
+{-# OPTIONS_GHC -Wno-missing-export-lists #-}
+module Day06 where
+
+import Test.Tasty
+import Test.Tasty.HUnit
+import Solutions.Day06 (parser, part1, part2)
+
+exampleInput :: String
+exampleInput = "Time:      7  15   30\n\
+               \Distance:  9  40  200"
+
+test_day06 :: TestTree
+test_day06 = testGroup "Day06"
+  [
+    testCase "parser" $ do
+      parser exampleInput @?= [(7, 9), (15, 40), (30, 200)],
+
+    testCase "part 1 - example input" $ do
+      part1 (parser exampleInput) @?= 288,
+
+    testCase "part 1" $ do
+      input <- parser <$> readFile "data/day06.txt"
+      part1 input @?= 138915,
+
+    testCase "part 2 - example input" $ do
+      part2 (parser exampleInput) @?= 71503,
+
+    testCase "part 2" $ do
+      input <- parser <$> readFile "data/day06.txt"
+      part2 input @?= 27340847
+  ]
+