Day 1

.gitignore

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+result*
+*.cabal

Main.hs

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+module Main where
+
+import Day1
+
+main :: IO ()
+main = do
+  putStrLn "AoC 2023"
+  putStrLn "Day 1"
+  Day1.main

flake.lock

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+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1703134684,
+        "narHash": "sha256-SQmng1EnBFLzS7WSRyPM9HgmZP2kLJcPAz+Ug/nug6o=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "d6863cbcbbb80e71cecfc03356db1cda38919523",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

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+{
+  description = "A Hello World for AoC";
+  inputs.nixpkgs.url = "nixpkgs";
+  outputs = { self, nixpkgs }:
+    let
+      supportedSystems = [ "x86_64-linux" "x86_64-darwin" ];
+      forAllSystems = f: nixpkgs.lib.genAttrs supportedSystems (system: f system);
+      nixpkgsFor = forAllSystems (system: import nixpkgs {
+        inherit system;
+        overlays = [ self.overlay ];
+      });
+    in
+    {
+      overlay = (final: prev: {
+        aoc23 = final.haskellPackages.callCabal2nix "aoc23" ./. {};
+      });
+      packages = forAllSystems (system: {
+         aoc23 = nixpkgsFor.${system}.aoc23;
+      });
+      defaultPackage = forAllSystems (system: self.packages.${system}.aoc23);
+      checks = self.packages;
+      devShell = forAllSystems (system: let haskellPackages = nixpkgsFor.${system}.haskellPackages;
+        in haskellPackages.shellFor {
+          packages = p: [self.packages.${system}.aoc23];
+          withHoogle = true;
+          buildInputs = with haskellPackages; [
+            haskell-language-server
+            ghcid
+            cabal-install
+          ];
+        # Change the prompt to show that you are in a devShell
+        shellHook = ''
+          hpack
+        '';
+        });
+  };
+}

inputs/day1-test.input

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+1abc2
+pqr3stu8vwx
+a1b2c3d4e5f
+treb7uchet

inputs/day1-test2.input

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+two1nine
+eightwothree
+abcone2threexyz
+xtwone3four
+4nineeightseven2
+zoneight234
+7pqrstsixteen

package.yaml

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+name: aoc23
+
+ghc-options: -Wall -threaded
+
+default-extensions:
+  - OverloadedStrings
+
+dependencies:
+  - base == 4.*
+  - attoparsec
+  - bytestring
+
+executables:
+  aoc23:
+    main: Main.hs
+    dependencies:
+      - aoc23
+
+library:
+  source-dirs: src
+  exposed-modules:
+    - Day1
+

src/Day1.hs

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+{-# LANGUAGE OverloadedStrings #-}
+{-# OPTIONS_GHC -Wno-unused-do-bind #-}
+
+module Day1 where
+
+import Data.Semigroup
+import Data.Char
+import Data.String
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Char8 as Char8
+import Data.Attoparsec.Lazy
+import Data.Attoparsec.ByteString.Char8 (letter_ascii)
+import Data.Either (fromRight)
+
+-- import Debug.Trace
+
+main :: IO ()
+main = do
+  day1input <- lines <$> readFile "inputs/day1.input"
+  putStrLn "Part 1 result:"
+  print $ part1 day1input
+  putStrLn "Part 2 result:"
+  print $ part2 day1input
+
+part1 :: [String] -> Sum Int
+part1 = foldMap go
+  where
+    go :: String -> Sum Int
+    go = glueFirstLast . map (\c -> read [c]) . filter isNumber
+
+part2 :: [String] -> Sum Int
+part2 = foldMap (glueFirstLast . getNumbers)
+
+glueFirstLast :: [Int] -> Sum Int
+glueFirstLast xs = Sum $ 10 * head xs + last xs
+
+getNumbers :: String -> [Int]
+getNumbers = fromRight [] . parseOnly numberParser . fromString
+
+numberParser :: Parser [Int]
+numberParser = do
+  s <- concat <$> (parseN `sepBy` letter_ascii)
+  pure $ concatMap toInt s
+  where
+    parseN = many' . choice $ map string
+      ["oneight","threeight","fiveight","sevenine","nineight","eightwo","eighthree","twone"
+      ,"one","two","three","four","five","six","seven","eight","nine"
+      , "1","2","3","4","5","6","7","8","9"
+      ]
+    toInt :: B.ByteString -> [Int]
+    toInt "one" = [1]
+    toInt "two" = [2]
+    toInt "three" = [3]
+    toInt "four" = [4]
+    toInt "five" = [5]
+    toInt "six" = [6]
+    toInt "seven" = [7]
+    toInt "eight" = [8]
+    toInt "nine" = [9]
+    toInt "oneight" = [1,8]
+    toInt "threeight" = [3,8]
+    toInt "fiveight" = [5,8]
+    toInt "sevenine" = [7,9]
+    toInt "nineight" = [9,8]
+    toInt "eighthree" = [8,3]
+    toInt "eightwo" = [8,2]
+    toInt "twone" = [2,1]
+    toInt ss = [read $ Char8.unpack ss]