this post was submitted on 07 Dec 2024
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Advent Of Code

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An unofficial home for the advent of code community on programming.dev!

Advent of Code is an annual Advent calendar of small programming puzzles for a variety of skill sets and skill levels that can be solved in any programming language you like.

AoC 2024

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Day 7: Bridge Repair

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[โ€“] [email protected] 3 points 2 weeks ago (1 children)

Haskell

I'm not very proud, I copied my code for part two.

import Control.Arrow hiding (first, second)

import qualified Data.List as List
import qualified Data.Char as Char

parseLine l = (n, os)
        where
                n = read . takeWhile (Char.isDigit) $ l
                os = map read . drop 1 . words $ l

parse :: String -> [(Int, [Int])]
parse s = map parseLine . takeWhile (/= "") . lines $ s

insertOperators target (r:rs) = any (target ==) (insertOperators' r rs)
insertOperators' :: Int -> [Int] -> [Int]
insertOperators' acc []     = [acc]
insertOperators' acc (r:rs) = insertOperators' (acc+r) rs ++ insertOperators' (acc*r) rs

insertOperators2 target (r:rs) = any (target ==) (insertOperators2' r rs)
insertOperators2' :: Int -> [Int] -> [Int]
insertOperators2' acc []     = [acc]
insertOperators2' acc (r:rs) = insertOperators2' (acc+r) rs ++ insertOperators2' (acc*r) rs ++ insertOperators2' concatN rs
        where
                concatN = read (show acc ++ show r)

part1 ls = filter (uncurry insertOperators)
        >>> map fst
        >>> sum
        $ ls
part2 ls = filter (uncurry insertOperators2)
        >>> map fst
        >>> sum
        $ ls

main = getContents >>= print . (part1 &&& part2) . parse
[โ€“] [email protected] 2 points 2 weeks ago

If you get the right answer, it's ok ๐Ÿ‘