結果

問題 No.955 ax^2+bx+c=0
ユーザー Leonardone
提出日時 2019-12-18 04:11:15
言語 Haskell
(9.10.1)
結果
WA  
実行時間 -
コード長 1,272 bytes
コンパイル時間 2,052 ms
コンパイル使用メモリ 173,056 KB
実行使用メモリ 10,528 KB
最終ジャッジ日時 2024-07-07 00:29:34
合計ジャッジ時間 6,964 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge4
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 AC * 3
other AC * 48 WA * 26 TLE * 1 -- * 47
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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:4:75: warning: [GHC-63394] [-Wx-partial]
    In the use of ‘head’
    (imported from Prelude, but defined in GHC.List):
    "This is a partial function, it throws an error on empty lists. Use pattern matching or Data.List.uncons instead. Consider refactoring to use Data.List.NonEmpty."
  |
4 | main = interact $ unlines . concat . zipWith ($) [return . show . floor . head, map show . tail] . repeat . solve . map read . words
  |                                                                           ^^^^

Main.hs:4:92: 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."
  |
4 | main = interact $ unlines . concat . zipWith ($) [return . show . floor . head, map show . tail] . repeat . solve . map read . words
  |                                                                                            ^^^^
[2 of 2] Linking a.out

ソースコード

diff # 

-- Try yukicoder
-- author: Leonardone @ NEETSDKASU

main = interact $ unlines . concat . zipWith ($) [return . show . floor . head, map show . tail] . repeat . solve . map read . words

solve (0:0:0:_) = [-1]
solve (0:0:_:_) = [0]
solve (0:b:c:_) = [1, fromIntegral (-c) / fromIntegral b]
solve (a:0:0:_) = [1, 0]
solve (a:0:c:_) | e < 0     = undefined -- [0]
                | otherwise = undefined -- [2, - sqrt e, sqrt e]
                where e = fromIntegral (-c) / fromIntegral a
solve (a:b:0:_) = undefined -- [2, min 0 x, max 0 x]
                where x = fromIntegral (-b) / fromIntegral a
solve (a:b:c:_) | d < 0  = [0]
                | d == 0 = [1, 0.5 * (fromIntegral (-b) / fromIntegral a)]
                | d > 0  = [2, min y z, max y z]
                where d = b * b - 4 * a * c
                      y = 0.5 * (fromIntegral (-b) / fromIntegral a + sqrt' (fromIntegral d / fromIntegral a / fromIntegral a))
                      z = 0.5 * (fromIntegral (-b) / fromIntegral a - sqrt' (fromIntegral d / fromIntegral a / fromIntegral a))
solve _ = undefined


sqrt' x = fst $ until (f x) (g x) (x, (0, x))
f x (e,_) = abs (x - e * e) < 1e-12
g x (_,(y,z)) | e * e < x = (e,(e,z))
              | otherwise = (e,(y,e))
              where e = (y + z) / 2
0