title: Efficient Way To Multiply With 7
signature: efficientWayToMultiplyWith7 :: Integer -> Integer
  efficientWayToMultiplyWith7 n = 
test_code: import Text.Printf
  import Control.Exception (catch, SomeException)
  import Data.Typeable
  import qualified Data.List as List
  import qualified Data.Map as Map
  import qualified Data.Set as Set
  
  -- SOLUTION CODE
  -- ============================================
  
  PLACEHOLDER_CODE_BODY
  
  -- TESTING CODE 
  -- ============================================
  validateSolution :: Integer -> Integer -> Bool
  validateSolution actual expected = do
      actual == expected
  
  
  driver :: Integer -> Integer -> String
  driver n expected = do
      if (validateSolution (PLACEHOLDER_FN_NAME n) expected)
          then "PASSED"
      else "FAILED"
  
  main = do
      printf "TEST-0...%s\n" (driver (41) (287) )
  
      printf "TEST-1...%s\n" (driver (42) (294) )
  
      printf "TEST-2...%s\n" (driver (62) (434) )
  
      printf "TEST-3...%s\n" (driver (4) (28) )
  
      printf "TEST-4...%s\n" (driver (31) (217) )
  
      printf "TEST-5...%s\n" (driver (75) (525) )
  
      printf "TEST-6...%s\n" (driver (5) (35) )
  
      printf "TEST-7...%s\n" (driver (75) (525) )
  
      printf "TEST-8...%s\n" (driver (85) (595) )
  
      printf "TEST-9...%s\n" (driver (19) (133) )
  
source_py: def efficient_way_to_multiply_with_7(n):
      return ((n << 3) - n)
source_cpp: long efficient_way_to_multiply_with_7(long n) {
    return ( ( n << 3 ) - n );
  }