結果

問題 No.52 よくある文字列の問題
コンテスト
ユーザー gemmaro
提出日時 2020-07-25 12:18:10
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
AC  
実行時間 4 ms / 5,000 ms
コード長 711 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 1,504 ms
コンパイル使用メモリ 194,432 KB
実行使用メモリ 6,400 KB
最終ジャッジ日時 2026-03-14 04:48:14
合計ジャッジ時間 2,477 ms
ジャッジサーバーID
（参考情報） 		judge3_0 / judge1_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 * 11
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:12:39: 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"."
   |
12 |                 l = possibleStrings' (tail s) [[head s]]
   |                                       ^^^^

Main.hs:12:49: 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"."
   |
12 |                 l = possibleStrings' (tail s) [[head s]]
   |                                                 ^^^^

Main.hs:19:48: 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"."
   |
19 |                         l' = possibleStrings' (tail t) (map (\y -> head t:y) x)
   |                                                ^^^^

Main.hs:19:68: 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"."
   |
19 |                         l' = possibleStrings' (tail t) (map (\y ->

ソースコード

diff #
raw source code 

import qualified Data.List as L

main :: IO ()
main = print . solve =<< getLine

solve :: String -> Int
solve = length . L.nub . possibleStrings
    where
        possibleStrings :: String -> [String]
        possibleStrings s = l ++ r
            where
                l = possibleStrings' (tail s) [[head s]]
                r = possibleStrings' (init s) [[last s]]

                possibleStrings' :: String -> [String] -> [String]
                possibleStrings' [] x = x
                possibleStrings' t x = l' ++ r'
                    where
                        l' = possibleStrings' (tail t) (map (\y -> head t:y) x)
                        r' = possibleStrings' (init t) (map (\y -> last t:y) x)
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