Day 07 solution

day07a/.gitignore

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+.stack-work/
+*~

day07a/day07a.cabal

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+cabal-version: 1.12
+
+-- This file has been generated from package.yaml by hpack version 0.36.0.
+--
+-- see: https://github.com/sol/hpack
+
+name:           day07a
+version:        0.1.0.0
+description:    Please see the README at <https://git.astolfo.cool/natty/aoc23#readme>
+author:         Natty
+maintainer:     natty.sh.git@gmail.com
+copyright:      2023 Natty
+build-type:     Simple
+
+executable day07a
+  main-is: Main.hs
+  other-modules:
+      Paths_day07a
+  hs-source-dirs:
+      src
+  ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wmissing-export-lists -Wmissing-home-modules -Wpartial-fields -Wredundant-constraints -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      base >=4.7 && <5
+    , containers
+    , extra
+    , megaparsec
+    , text
+  default-language: Haskell2010

day07a/package.yaml

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+name:                day07a
+version:             0.1.0.0
+author:              "Natty"
+maintainer:          "natty.sh.git@gmail.com"
+copyright:           "2023 Natty"
+
+description:         Please see the README at <https://git.astolfo.cool/natty/aoc23#readme>
+
+dependencies:
+- base >= 4.7 && < 5
+- megaparsec
+- containers
+- text
+- extra
+
+ghc-options:
+- -Wall
+- -Wcompat
+- -Widentities
+- -Wincomplete-record-updates
+- -Wincomplete-uni-patterns
+- -Wmissing-export-lists
+- -Wmissing-home-modules
+- -Wpartial-fields
+- -Wredundant-constraints
+
+executables:
+  day07a:
+    main:                Main.hs
+    source-dirs:         src
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N

day07a/src/Main.hs

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+{-# LANGUAGE ViewPatterns #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+
+module Main (main) where
+import qualified Data.Text as T
+import Data.List ( elemIndex, sort, sortBy, group )
+import Data.Maybe (fromJust)
+import GHC.Num (integerFromInt)
+import Data.Function (on)
+import Data.Ord (comparing, Down (Down))
+
+cardStrength :: Char -> Integer
+cardStrength = integerFromInt . fromJust . flip elemIndex (reverse "AKQJT98765432")
+
+countTypes :: [Char] -> [Int]
+countTypes = sortBy (comparing Down) . (length <$>) . group . sort
+
+handStrength :: [Char] -> Integer
+handStrength cc = case countTypes cc of 
+    [5] -> 6 -- 5 of a kind
+    [4, 1] -> 5 -- 4 of a kind
+    [3, 2] -> 4 -- full house
+    [3, 1, 1] -> 3 -- 3 of a kind
+    [2, 2, 1] -> 2 -- two pairs
+    [2, 1, 1, 1] -> 1 -- a pair
+    [1, 1, 1, 1, 1] -> 0 -- nothing
+    _ -> error "Unreachable"
+
+parseHand :: [T.Text] -> ([Char], Integer)
+parseHand [T.unpack -> hand, read . T.unpack -> bid :: Integer] = (hand, bid)
+parseHand _ = error "Parse error"
+
+cmpHands :: [Char] -> [Char] -> Ordering
+cmpHands = comparing handStrength <> comparing (fmap cardStrength)
+
+main :: IO ()
+main = do
+    hands <- (parseHand . T.words . T.pack <$>) . lines <$> getContents
+    print $ sum . zipWith (*) [1..] $ snd <$> sortBy (cmpHands `on` fst) hands

day07a/stack.yaml

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+resolver: lts-21.21
+
+packages:
+- .
+
+extra-deps: []

day07a/stack.yaml.lock

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+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages: []
+snapshots:
+- completed:
+    sha256: 7d4b649cf368f9076d8aa049aa44efe58950971d105892734e9957b2a26a2186
+    size: 640060
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/21/21.yaml
+  original: lts-21.21

day07a/test.txt

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+32T3K 765
+T55J5 684
+KK677 28
+KTJJT 220
+QQQJA 483

day07b/.gitignore

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+.stack-work/
+*~

day07b/day07b.cabal

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+cabal-version: 1.12
+
+-- This file has been generated from package.yaml by hpack version 0.36.0.
+--
+-- see: https://github.com/sol/hpack
+
+name:           day07b
+version:        0.1.0.0
+description:    Please see the README at <https://git.astolfo.cool/natty/aoc23#readme>
+author:         Natty
+maintainer:     natty.sh.git@gmail.com
+copyright:      2023 Natty
+build-type:     Simple
+
+executable day07b
+  main-is: Main.hs
+  other-modules:
+      Paths_day07b
+  hs-source-dirs:
+      src
+  ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wmissing-export-lists -Wmissing-home-modules -Wpartial-fields -Wredundant-constraints -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      base >=4.7 && <5
+    , containers
+    , megaparsec
+    , text
+  default-language: Haskell2010

day07b/package.yaml

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+name:                day07b
+version:             0.1.0.0
+author:              "Natty"
+maintainer:          "natty.sh.git@gmail.com"
+copyright:           "2023 Natty"
+
+description:         Please see the README at <https://git.astolfo.cool/natty/aoc23#readme>
+
+dependencies:
+- base >= 4.7 && < 5
+- megaparsec
+- containers
+- text
+
+ghc-options:
+- -Wall
+- -Wcompat
+- -Widentities
+- -Wincomplete-record-updates
+- -Wincomplete-uni-patterns
+- -Wmissing-export-lists
+- -Wmissing-home-modules
+- -Wpartial-fields
+- -Wredundant-constraints
+
+executables:
+  day07b:
+    main:                Main.hs
+    source-dirs:         src
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N

day07b/src/Main.hs

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+{-# LANGUAGE ViewPatterns #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+
+module Main (main) where
+import qualified Data.Text as T
+import Data.List ( elemIndex, sort, sortBy, group, maximumBy )
+import Data.Maybe (fromJust)
+import GHC.Num (integerFromInt)
+import Data.Function (on)
+import Data.Ord (comparing, Down (Down))
+
+cardStrength :: Char -> Integer
+cardStrength = integerFromInt . fromJust . flip elemIndex (reverse "AKQT98765432J")
+
+countTypes :: [Char] -> [Int]
+countTypes = sortBy (comparing Down) . (length <$>) . group . sort
+
+handStrength :: [Char] -> Integer
+handStrength cc = case countTypes cc of
+    [5] -> 6 -- 5 of a kind
+    [4, 1] -> 5 -- 4 of a kind
+    [3, 2] -> 4 -- full house
+    [3, 1, 1] -> 3 -- 3 of a kind
+    [2, 2, 1] -> 2 -- two pairs
+    [2, 1, 1, 1] -> 1 -- a pair
+    [1, 1, 1, 1, 1] -> 0 -- nothing
+    _ -> error "Unreachable"
+
+replaceJokers :: Char -> [Char] -> [Char]
+replaceJokers c = fmap (\cc -> if cc == 'J' then c else cc)
+
+maxJokerHand :: [Char] -> Char
+maxJokerHand hand = maximumBy (compare `on` handStrength . flip replaceJokers hand) "AKQJT98765432"
+
+maximizeHand :: [Char] -> [Char]
+maximizeHand = replaceJokers =<< maxJokerHand
+
+parseHand :: [T.Text] -> ([Char], Integer)
+parseHand [T.unpack -> hand, read . T.unpack -> bid :: Integer] = (hand, bid)
+parseHand _ = error "Parse error"
+
+cmpHands :: [Char] -> [Char] -> Ordering
+cmpHands = comparing (handStrength . maximizeHand)
+    <> comparing (fmap cardStrength)
+
+main :: IO ()
+main = do
+    hands <- (parseHand . T.words . T.pack <$>) . lines <$> getContents
+    print $ sum . zipWith (*) [1..] $ snd <$> sortBy (cmpHands `on` fst) hands

day07b/stack.yaml

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+resolver: lts-21.21
+
+packages:
+- .
+
+extra-deps: []

day07b/stack.yaml.lock

@@ -0,0 +1,12 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages: []
+snapshots:
+- completed:
+    sha256: 7d4b649cf368f9076d8aa049aa44efe58950971d105892734e9957b2a26a2186
+    size: 640060
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/21/21.yaml
+  original: lts-21.21

day07b/test.txt

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+32T3K 765
+T55J5 684
+KK677 28
+KTJJT 220
+QQQJA 483

run.sh

@@ -25,7 +25,8 @@ case "$1" in
     "day02a" | "day02b" | \
     "day03a" | "day03b" | \
     "day04a" | "day04b" | \
-    "day06a" | "day06b" ) stack run <input.txt
+    "day06a" | "day06b" | \
+    "day07a" | "day07b" ) stack run <input.txt
        ;;
     # Default solutions -- Java
     *) ./gradlew run <input.txt

test.sh

@@ -25,7 +25,8 @@ case "$1" in
     "day02a" | "day02b" | \
     "day03a" | "day03b" | \
     "day04a" | "day04b" | \
-    "day06a" | "day06b") stack run <test.txt
+    "day06a" | "day06b" | \
+    "day07a" | "day07b" ) stack run <test.txt
        ;;
     # Default solutions -- Java
     *) ./gradlew run <test.txt