Submission #162542

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Source Code Expand

import Control.Applicative
main = do
  [x,y] <- map read <$> words <$> getLine
  print $ ans y - ans (x-1)

ans :: Integer -> Integer
ans x = x - oct x

oct :: Integer -> Integer
oct x = toOct 0 $ miniE $ map (read . return) $ show x

miniE :: [Integer] -> [Integer]
miniE [] = []
miniE (y:xs)
  | y == 9 = 7 : map (const 7) xs
  | y == 4 = 3 : map (const 7) xs
  | y >= 4 = (y-1) : miniE xs
  | otherwise = y : miniE xs

toOct :: Integer -> [Integer] -> Integer
toOct u [] = u
toOct u (x:xs) = toOct (u*8+x) xs

Submission Info

Judge Result