Problem:
Score : 200 points

Problem Statement

An integer X is called a Harshad number if X is divisible by f(X), where f(X) is the sum of the digits in X when written in base 10.

Given an integer N, determine whether it is a Harshad number.

Constraints

1?N?10^8

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print Yes if N is a Harshad number; print No otherwise.

Sample Input 1

12

Sample Output 1

Yes

f(12)=1+2=3. Since 12 is divisible by 3, 12 is a Harshad number.

Sample Input 2

57

Sample Output 2

No

f(57)=5+7=12. Since 57 is not divisible by 12, 12 is not a Harshad number.

Sample Input 3

148

Sample Output 3

No

Solution in Haskell (GHC 7.10.3) (judge verdict: Accepted)

import qualified Data.ByteString.Char8 as C
import Data.Maybe ( fromJust )
import Data.Char ( digitToInt )

readInt :: IO Int
readInt = fst . fromJust . C.readInt <$> C.getLine

main :: IO ()
main = do
  n <- readInt
  putStrLn $ if isHarshad n then "Yes" else "No"

isHarshad
  :: Int -> Bool
isHarshad x 
  = let fx = sumDigits x  
    in 0 == x `rem` fx

sumDigits, sumDigits'
  :: Int -> Int
sumDigits = sum . map digitToInt . show

sumDigits' = sum . int2lst
int2lst n
  | q == 0 = [r]
  | otherwise = r : int2lst q
  where
    (q,r) = divMod n 10