結果

問題 No.326 あみだますたー
コンテスト
ユーザー aimy
提出日時 2017-04-24 23:05:39
言語 Haskell
(9.10.1)
結果
WA  
実行時間 -
コード長 726 bytes
コンパイル時間 3,835 ms
コンパイル使用メモリ 171,008 KB
実行使用メモリ 10,624 KB
最終ジャッジ日時 2024-09-13 12:11:30
合計ジャッジ時間 6,679 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge1
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 WA * 2
other AC * 5 WA * 21
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:10:20: 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."
   |
10 |  is <- map (read . head . words) <$> replicateM k getLine
   |                    ^^^^

Main.hs:23:17: 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."
   |
23 |  let xi = fst $ head $ dropWhile (uncurry (==)) $ zip goal xs
   |                 ^^^^
[2 of 2] Linking a.out

ソースコード

diff # 

import Control.Monad
import Data.List (foldl', findIndex, unfoldr)

replace i xs = xs1 ++ (xj : xi : xs2)
 where (xs1,(xi:xj:xs2)) = splitAt (i-2) xs

main = do
 n <- readLn
 k <- readLn
 is <- map (read . head . words) <$> replicateM k getLine
 goal <- map read . words <$> getLine
 let start = amida [1..n] is
 let inss = unfoldr (insert goal) start
 print (length inss)
 putStr $ (unlines . map (unwords . map show)) inss

amida :: [Int] -> [Int] -> [Int]
amida xs = foldl' (flip replace) xs

insert :: [Int] -> [Int] -> Maybe ([Int],[Int])
insert goal xs = do
 guard (goal /= xs)
 let xi = fst $ head $ dropWhile (uncurry (==)) $ zip goal xs
 i <- succ <$> findIndex (==xi) xs 
 let ji = [i-1,i]
 return (ji, replace i xs)
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