結果

問題 No.4 おもりと天秤
コンテスト
ユーザー e7a894
提出日時 2018-05-21 22:56:14
言語 Haskell
(9.14.1)
コンパイル:
ghc -rtsopts -with-rtsopts=-K1G -o a.out -O2 _filename_
実行:
./a.out
結果
WA  
実行時間 -
コード長 578 bytes
記録
記録タグの例:
初AC ショートコード 純ショートコード 純主流ショートコード 最速実行時間
コンパイル時間 5,188 ms
コンパイル使用メモリ 195,584 KB
実行使用メモリ 9,984 KB
最終ジャッジ日時 2026-03-17 13:27:27
合計ジャッジ時間 1,819 ms
ジャッジサーバーID
（参考情報） 		judge1_0 / judge2_0
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
other AC * 21 WA * 2
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-9.14.1/environments/default
[1 of 2] Compiling Main             ( Main.hs, Main.o )
Main.hs:16:14: warning: [GHC-63394] [-Wx-partial]
    In the use of ‘head’
    (imported from Prelude, but defined in GHC.Internal.List):
    "This is a partial function, it throws an error on empty lists. Use pattern matching, 'Data.List.uncons' or 'Data.Maybe.listToMaybe' instead. Consider refactoring to use "Data.List.NonEmpty"."
   |
16 |       | a + (head bs) > e = resolve' ((a, tail bs):ps)
   |              ^^^^

Main.hs:16:43: warning: [GHC-63394] [-Wx-partial]
    In the use of ‘tail’
    (imported from Prelude, but defined in GHC.Internal.List):
    "This is a partial function, it throws an error on empty lists. Replace it with 'drop' 1, or use pattern matching or 'GHC.Internal.Data.List.uncons' instead. Consider refactoring to use "Data.List.NonEmpty"."
   |
16 |       | a + (head bs) > e = resolve' ((a, tail bs):ps)
   |                                           ^^^^

Main.hs:17:37: warning: [GHC-63394] [-Wx-partial]
    In the use of ‘head’
    (imported from Prelude, but defined in GHC.Internal.List):
    "This is a partial function, it throws an error on empty lists. Use pattern matching, 'Data.List.uncons' or 'Data.Maybe.listToMaybe' instead. Consider refactoring to use "Data.List.NonEmpty"."
   |
17 |       | otherwise = resolve' ((a + (head bs), tail bs):(a, tail bs):ps)
   |                                     ^^^^

Main.hs:17:47: warning: [GHC-63394] [-Wx-partial]
    In the use of ‘tail’
    (imported from Prelude, but defined in GHC.Internal.List):
    "This is a partial function, it throws an error on empty lists. Replace it with 'drop' 1, or use pattern matching or 'GHC.Internal.Data.List.uncons' instead. Consider refactoring to use "Data.List.NonEmpty"."
   |
17 |       | otherwise = resolve' ((a + (head bs), tail bs):(a, tail bs):ps)
   |

ソースコード

diff #
raw source code 

main = do
  n <- readLn :: IO Int
  ws <- (map read . words) <$> getLine
  let e = (sum ws) `div` 2
  let ws' = filter (<= e) ws
  putStrLn $ if (odd $ sum ws) || (sum ws' < e) then "impossible" else resolve e ws'

resolve e ws = resolve' [(0, ws)]
  where
    resolve' :: [(Int, [Int])] -> String
    resolve' [] = "impossible"
    resolve' ((a,bs):ps)
      | a == e = "possible"
      | null bs = resolve' ps
      | sum bs < (e - a) = "impossible"
      | a + (head bs) > e = resolve' ((a, tail bs):ps)
      | otherwise = resolve' ((a + (head bs), tail bs):(a, tail bs):ps)
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