title: Efficient Way To Multiply With 7
signature: efficientWayToMultiplyWith7(n) {
test_code: import 'dart:convert';
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  bool validateSolution(int actual, int expected){
      return actual.toString() == expected.toString();
  }
  
  String driver(n, int expected){
      try
      {
          if (validateSolution(PLACEHOLDER_FN_NAME(n), expected)){
              return "PASSED";
          }
          return "FAILED";
      }catch(exception_object){
          return exception_object.runtimeType.toString();
      }
  }
  
  int main() {
  
      print("TEST-0...${driver(
          41, 
          287)
      }");
  
      print("TEST-1...${driver(
          42, 
          294)
      }");
  
      print("TEST-2...${driver(
          62, 
          434)
      }");
  
      print("TEST-3...${driver(
          4, 
          28)
      }");
  
      print("TEST-4...${driver(
          31, 
          217)
      }");
  
      print("TEST-5...${driver(
          75, 
          525)
      }");
  
      print("TEST-6...${driver(
          5, 
          35)
      }");
  
      print("TEST-7...${driver(
          75, 
          525)
      }");
  
      print("TEST-8...${driver(
          85, 
          595)
      }");
  
      print("TEST-9...${driver(
          19, 
          133)
      }");
  
      return 0;
  }
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 );
  }