module Main where import Data.Foldable (toList) import Data.Maybe (catMaybes) import Data.Ord (comparing) import Data.List (minimumBy) import Input import Util ceilDiv :: Integral a => a -> a -> a ceilDiv a b = (a + b - 1) `div` b -- Returns (gcd m n, (x, y)) such that x * m + y * m = gcd m n egcd :: Integral a => a -> a -> (a, (a, a)) egcd m n = egcd' 1 0 m 0 1 n where egcd' x y g _ _ 0 = (g, (x, y)) egcd' x y g x2 y2 g2 = -- invariant: x * m + y * n = g && x2 * m + y2 * n = g2 let (q, r) = g `divMod` g2 in egcd' x2 y2 g2 (x - q * x2) (y - q * y2) r crt :: Integral a => (a, a) -> (a, a) -> (a, a) crt (x, m) (y, n) | (1, (u, v)) <- egcd m n = ((x * v * n + y * u * m) `mod` (n * m), n * m) | otherwise = error "crt: non-coprime moduli" crt' :: Integral a => [(a, a)] -> a crt' = fst . foldl1 crt main :: IO () main = do [deptimestr, ivsstr] <- getInput 13 let arrivetime = read deptimestr :: Integer ivs = [if x == "x" then Nothing else Just (read x) | x <- toList (splitOn (== ',') ivsstr)] (earliest, leavetime) = minimumBy (comparing snd) [(iv, arrivetime `ceilDiv` iv * iv) | iv <- catMaybes ivs] print (earliest * (leavetime - arrivetime)) print (crt' [(iv - idx, iv) | (Just iv, idx) <- zip ivs [0..]])