AoC2019/day16.hs

31 lines
1.0 KiB
Haskell

import Data.Char
main = do
content <- getContents
let input = map digitToInt $ init content
let base = [0,1,0,-1]
let patter = map (getPatternForIndex base (length input)) [0..(length input)]
let test1 = doSteps input patter 100
--putStrLn (show input)
--mapM putStrLn (map show patter)
putStrLn (show test1)
getPatternForIndex :: [Int] -> Int -> Int -> [Int]
getPatternForIndex patter length index = drop (1 + index) $ take (length +1) (cycle base)
where base = concat $ map (replicate (index+1)) patter
getInputForIndex :: [Int] -> Int -> [Int]
getInputForIndex xs index = drop index xs
get :: [Int] -> Int
get xs = mod (abs $ (sum xs)) 10
step :: [Int] -> [[Int]] -> [Int]
step xs patterns = map (\(a,b) -> get( zipWith (*) a b)) $ zip inputs patterns
where inputs = map (getInputForIndex xs) [0..(length patterns)]
doSteps :: [Int] -> [[Int]] -> Int -> [Int]
doSteps xs patterns cnt
| cnt == 0 = xs
| otherwise = doSteps (step xs patterns) patterns (cnt -1)