Jassob/aoc-25
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

feat: solve part 2 of day 2

Browse source
This commit is contained in:
Jacob Jonsson 2025-12-02 15:48:54 +01:00
parent 2e8920cae1
commit 3f0d19a5d1
1 changed files with 19 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

21
app/Day2.hs
View file

@ -1,13 +1,13 @@
module Main where module Main where
import Debug.Trace
import System.Environment (getArgs) import System.Environment (getArgs)
main :: IO () main :: IO ()
main = do main = do
input <- readFile . head =<< getArgs input <- readFile . head =<< getArgs
print $ part1 input print $ part1 input
print $ part2 input
-- print $ part2 input
part1 :: String -> Int part1 :: String -> Int
part1 = sum . filter invalid . concat . map ids . map parse . splitOn ',' part1 = sum . filter invalid . concat . map ids . map parse . splitOn ','
@ -36,4 +36,21 @@ invalid i =
half = take (len `div` 2) s half = take (len `div` 2) s
in s == half ++ half in s == half ++ half
part2 :: String -> Int
part2 = sum . filter invalid2 . concat . map ids . map parse . splitOn ','
invalid2 :: Int -> Bool
invalid2 i =
let s = show i
len = length s
facs = factors len
in or [(repeatN (len `div` n) $ take n s) == s | n <- facs]
-- needs to get the primes instead of all factors
factors :: Int -> [Int]
factors i = filter ((== 0) . (mod i)) [1 .. i `div` 2]
repeatN :: Int -> [a] -> [a]
repeatN i = concat . replicate i
testInput = "11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124" testInput = "11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124"