結果

問題 No.154 市バス
コンテスト
ユーザー AyachiGin
提出日時 2016-06-11 17:07:22
言語 Haskell
(9.10.1)
結果
TLE  
実行時間 -
コード長 1,051 bytes
コンパイル時間 11,466 ms
コンパイル使用メモリ 173,056 KB
実行使用メモリ 23,368 KB
最終ジャッジ日時 2024-10-13 08:25:53
合計ジャッジ時間 8,626 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge2
このコードへのチャレンジ
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ファイルパターン 結果
sample -- * 1
other TLE * 1 -- * 7
権限があれば一括ダウンロードができます
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:39:40: warning: [GHC-63394] [-Wx-partial]
    In the use of ‘tail’
    (imported from Prelude, but defined in GHC.List):
    "This is a partial function, it throws an error on empty lists. Replace it with drop 1, or use pattern matching or Data.List.uncons instead. Consider refactoring to use Data.List.NonEmpty."
   |
39 |                          else f (as ++ tail bs)
   |                                        ^^^^
[2 of 2] Linking a.out

ソースコード

diff # 

module Main where


main :: IO ()
main = do
  i <- readLn
  s <- getContents
  mapM_ (putStrLn . isPossible) . take i . lines $ s

-- | tests
-- >>> isPossible "WWWWWWWWWGR"
-- "possible"
-- >>> isPossible "WWWWGWGRR"
-- "possible"
-- >>> isPossible "WWWWWWWWWWWWWWGRRG"
-- "impossible"
-- >>> isPossible "WGRWGR"
-- "possible"
-- >>> isPossible "WWWWWWWWWWWWWWWWWGGWGWGGWGWGGGWGG"
-- "impossible"
-- >>> isPossible "WGWR"
-- "impossible"
-- >>> isPossible "WGRW"
-- "impossible"
isPossible :: String -> String
isPossible s = if take1RGW s then
                 "possible"
               else
                 "impossible"
  where
    take1RGW xs
      | length xs >= 3 && dropWhile (=='W') xs == "GR" = True
      | otherwise = takeW xs
    takeW ('W':xs) = takeG xs
    takeW _ = False
    takeX c ls f
      | c `elem` ls = let (as, bs) = break (==c) ls
                      in if null bs then False
                         else f (as ++ tail bs)
      | otherwise   = False
    takeG xs = takeX 'G' xs takeR
    takeR xs = takeX 'R' xs take1RGW
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