paiza Online Hackathon

_paiza

問題: https://paiza.jp/poh/kirishima
結果: http://paiza.jp/poh/kirishima/result/c7b9268a3c4b60e5c40aff903b3b9d96

paiza.hs

import Control.Applicative
import Data.List
import qualified Data.IntMap as IM
import Data.Ord

solve :: Int -> [[Int]] -> Int
solve n ps = getMin $ IM.assocs $ iter ps $ IM.singleton 0 0 where
  iter [] m = m
  iter (p:ps) m = iter ps $ IM.foldrWithKey' (go p) m m

  go [x,y] a b m = if a>=n then m else IM.insertWith' min (a+x) (y+b) m
  getMin ns = minimum [y|(x,y)<-ns, x>=n]

main = do
  m <- (read :: String -> Int) <$> getLine
  _ <- getLine
  ns <- fmap (fmap (read :: String -> Int) . words) . lines <$> getContents
  print $ solve m ns