結果

問題 No.489 株に挑戦
コンテスト
ユーザー aimy
提出日時 2017-08-31 14:31:51
言語 Haskell
(9.10.1)
結果
CE  
(最新)
AC  
(最初)
実行時間 -
コード長 2,012 bytes
コンパイル時間 1,053 ms
コンパイル使用メモリ 172,288 KB
最終ジャッジ日時 2024-11-14 20:14:33
合計ジャッジ時間 1,788 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge2
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コンパイルメッセージ
Loaded package environment from /home/judge/.ghc/x86_64-linux-9.8.2/environments/default
[1 of 2] Compiling Main             ( Main.hs, Main.o )

Main.hs:30:10: error: [GHC-39999]
    • No instance for ‘Semigroup V’
        arising from the superclasses of an instance declaration
    • In the instance declaration for ‘Monoid V’
   |
30 | instance Monoid V where
   |          ^^^^^^^^

ソースコード

diff # 

import Data.Monoid
import qualified Data.ByteString.Char8 as B

readInt :: B.ByteString -> Int
readInt = maybe undefined fst . B.readInt

readInts :: B.ByteString -> [Int]
readInts = map readInt . B.words

main = do
 [n,d,k] <- map read . words <$> getLine
 xs <- readInts <$> B.getContents
 let (pmax, (i,j)) = kabu n d xs
 print (k * pmax)
 if pmax == 0 then return () else putStrLn (show i ++ " " ++ show j)

kabu n d xs = foldl (slide n d seg) (0, (undefined, undefined)) (zip xs [0 .. n-2])
  where
    seg = fromList n (zipWith (\x i -> V x i) xs [0,-1..])

slide n d seg acc@(pmax,_) (x,i)
  | v - x > pmax = (v - x, (i, negate j))
  | otherwise = acc
  where
    (V v j) = query n seg (succ i + 1) (min (succ i + d) n)


data V = V Int Index deriving (Eq, Ord, Show)

instance Monoid V where
  mempty = V 0 undefined
  mappend = max

data SegTree m =
  Leaf !m |
  Node !m !(SegTree m) !(SegTree m)
  deriving (Eq, Show)

type Index = Int
type Size = Int

val :: Monoid m => SegTree m -> m
val (Leaf v) = v
val (Node v _ _) = v

fromList :: Monoid m => Size -> [m] -> SegTree m
fromList 1 [x] = Leaf x
fromList n xs = Node (val left <> val right) left right
  where
    m = div n 2
    (xs1, xs2) = splitAt m xs
    left = fromList m xs1
    right = fromList (n - m) xs2

update :: Monoid m => Size -> SegTree m -> Index -> (m -> m) -> SegTree m
update 1 (Leaf v) 1 f = Leaf (f v)
update _ (Leaf _) _ _ = error "update: Pattern match failed."
update n (Node _ l r) i x
  | i <= m = Node (val left <> val r) left r
  | otherwise = Node (val l <> val right) l right
  where
    m = div n 2
    left = update m l i x
    right = update (n - m) r (i - m) x

query :: Monoid m => Size -> SegTree m -> Index -> Index -> m
query 1 (Leaf v) 1 1 = v
query _ (Leaf _) _ _ = error "query: Pattern match failed."
query n (Node v l r) i j
  | (i, j) == (1, n) = v
  | j <= m = query m l i j
  | i > m = query (n - m) r (i - m) (j - m)
  | otherwise = query m l i m <> query (n - m) r 1 (j - m)
  where
    m = div n 2
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