Submission #75242458

---

Source Code Expand

{-# OPTIONS_GHC -Wall #-}
{-# OPTIONS_GHC -Wname-shadowing #-} -- 内側のスコープの値と同じ名前が外側のスコープにあるとき警告する

import Control.Monad
import qualified Data.ByteString.Char8 as BS
import Data.Char
import Data.List -- nub O(n^2)

readInts :: IO [Int]
readInts = unfoldr (BS.readInt . BS.dropWhile isSpace) <$> BS.getLine
readDoubles :: IO [Double]
readDoubles = map read . words . BS.unpack <$> BS.getLine

main :: IO ()
main = do
  [n,k] <- readInts
  as <- readInts
  let bs = sortBy (flip compare) $ map (\g -> (head g * length g)) $ group $ sort as
  if length bs <= k then
    print 0
  else do
    let cand = drop k bs
    print $ sum cand

Submission Info

Compile Error

Configuration is affected by the following files:
- cabal.project
- cabal.project.freeze
- cabal.project.local

app/Main.hs:4:1: warning: [GHC-66111] [-Wunused-imports]
    The import of ‘Control.Monad’ is redundant
      except perhaps to import instances from ‘Control.Monad’
    To import instances alone, use: import Control.Monad()
  |
4 | import Control.Monad
  | ^^^^^^^^^^^^^^^^^^^^

app/Main.hs:12:1: warning: [GHC-40910] [-Wunused-top-binds]
    Defined but not used: ‘readDoubles’
   |
12 | readDoubles = map read . words . BS.unpack <$> BS.getLine
   | ^^^^^^^^^^^

app/Main.hs:16:4: warning: [GHC-40910] [-Wunused-matches]
    Defined but not used: ‘n’
   |
16 |   [n,k] <- readInts
   |    ^

app/Main.hs:18:48: warning: [GHC-63394] [-Wx-partial]
    In the use of ‘head’
    (imported from Data.List, 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."
   |
18 |   let bs = sortBy (flip compare) $ map (\g -> (head g * length g)) $ group $ sort as
   |                                                ^^^^

app/Main.hs:20:5: warning: [GHC-18042] [-Wtype-defaults]
    • Defaulting the type variable ‘a0’ to type ‘Integer’ in the following constraints
        (Show a0) arising from a use of ‘print’ at app/Main.hs:20:5-9
        (Num a0) arising from the literal ‘0’ at app/Main.hs:20:11
    • In the expression: print 0
      In a stmt of a 'do' block:
        if length bs <= k then
            print 0
        else
            do let cand = ...
               print $ sum cand
      In the expression:
        do [n, k] <- readInts
           as <- readInts
           let bs = sortBy (flip compare) $ map (\ g -> ...) $ group $ sort as
           if length bs <= k then
               print 0
           else
               do let ...
                  ....
   |
20 |     print 0
   |     ^^^^^
Configuration is affected by the following files:
- cabal.project
- cabal.project.freeze
- cabal.project.local

Judge Result