Day1

.vscode/settings.json

@@ -1,6 +1,9 @@
 {
   "cSpell.words": [
+    "Bifunctor",
+    "bimap",
     "Collatz",
+    "Combinators",
     "concat",
     "coprime",
     "elems",

src/advent_of_code/2023/1.hs

@@ -0,0 +1,134 @@
+-- https://adventofcode.com/2023/day/1
+
+import           Data.Bifunctor               (bimap)
+import           Data.Maybe                   (fromMaybe)
+import           Text.ParserCombinators.ReadP (ReadP, choice, many, readP_to_S,
+                                               string, (<++))
+
+main :: IO ()
+main = do
+  entries <- lines <$> readFile "src/advent_of_code/2023/input1"
+  print "Advent of Code 2022 - Day 4"
+  -- print entries
+
+  print ("Part 1: " <> show (solveP1 entries))
+  print ("Part 2: " <> show (solveP2 entries))
+
+
+--
+-- Part 1
+--
+
+solveP1 :: [String] -> Int
+solveP1 = sum . map solveP1Line
+
+solveP1Line :: String -> Int
+solveP1Line = sumPairS . bimap head last . doubleString . filter isNumP1 . tokenized tokensP1
+
+tokensP1 :: ReadP String
+tokensP1 = parseNumberChars <++ parseChars
+
+--
+-- Part 2
+--
+
+solveP2 :: [String] -> Int
+solveP2 = sum . map solveP2Line
+
+--
+-- Need to parse from both sides
+-- "oneight" should return 18, not 11
+solveP2Line :: String -> Int
+solveP2Line = sumPairS . bimap a b . doubleString
+  where
+    a = head . condense . fromLeft
+    b = last . condense . fromRight
+
+    condense  = map stringToNum . filter isNumP2
+    fromLeft  =                         tokenized tokensP2
+    fromRight = map reverse . reverse . tokenized tokensP2' . reverse
+
+tokensP2 :: ReadP String
+tokensP2 = parseNumberWords <++ parseNumberChars <++ parseChars
+
+tokensP2' :: ReadP String
+tokensP2' = parseNumberWords' <++ parseNumberChars <++ parseChars
+
+solveP2LineBad :: String -> Int
+solveP2LineBad = sumPairS . bimap head last . doubleString . map stringToNum . filter isNumP2 . tokenized tokensP2
+
+--
+-- Utility functions
+--
+
+-- Doing this because I want to use a bifunctor
+doubleString :: str -> (str, str)
+doubleString    str =  (str, str)
+
+sumPairS :: (String, String) -> Int
+sumPairS (x,y) = read (x ++ y)
+
+stringToNum :: String -> String
+stringToNum str = fromMaybe str (lookup str $ zip numberWords numberChars)
+
+--
+-- Boilerplate equality checks
+-- Now condensed
+--
+
+isNumP1 :: String -> Bool
+isNumP1 = flip elem numberChars
+
+isNumP2 :: String -> Bool
+isNumP2 = flip elem (numberChars ++ numberWords)
+
+--
+-- Parsing for question
+--
+
+numberWords :: [String]
+numberWords = ["zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine"]
+
+numberChars :: [String]
+numberChars = map show [0..9]
+
+letterChars :: String
+letterChars = ['a'..'z']
+
+parseNumberWords :: ReadP String
+parseNumberWords = choice $ map string numberWords
+
+parseNumberWords' :: ReadP String
+parseNumberWords' = choice $ map (string . reverse) numberWords
+
+parseNumberChars :: ReadP String
+parseNumberChars = choice $ map string numberChars
+
+parseChars :: ReadP String
+parseChars = choice $ map (\c -> string [c]) letterChars
+
+tokenized :: ReadP a -> String -> [a]
+tokenized tokenSet = fst . last . readP_to_S (many tokenSet)
+
+--
+-- Examples
+--
+
+example1 :: [String]
+example1 =
+  [ "1abc2"
+  , "pqr3stu8vwx"
+  , "a1b2c3d4e5f"
+  , "treb7uchet"
+  ]
+
+example2 :: [String]
+example2 =
+  [ "two1nine"
+  , "eightwothree"
+  , "abcone2threexyz"
+  , "xtwone3four"
+  , "4nineeightseven2"
+  , "zoneight234"
+  , "7pqrstsixteen"
+  ]