title: Efficient Way To Multiply With 7
signature: pub fn efficient_way_to_multiply_with_7(n: i32) -> i32 {
test_code: use std::collections::HashMap;
  use std::collections::HashSet;
  use std::cmp::*;
  use std::collections::*;
  use std::fmt::*; 
  
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  pub fn validate_solution(actual: i32, expected: i32)->bool{
  return actual==expected
  }
  pub fn driver(n: i32, expected: i32)->String{
      if validate_solution(PLACEHOLDER_FN_NAME(n), expected) {
        return "PASSED".to_string();
      };
      return "FAILED".to_string();
  
  }
  
  fn main() {
      println!("TEST-0...{}", driver(
        41, 
        287
      ));
      
      println!("TEST-1...{}", driver(
        42, 
        294
      ));
      
      println!("TEST-2...{}", driver(
        62, 
        434
      ));
      
      println!("TEST-3...{}", driver(
        4, 
        28
      ));
      
      println!("TEST-4...{}", driver(
        31, 
        217
      ));
      
      println!("TEST-5...{}", driver(
        75, 
        525
      ));
      
      println!("TEST-6...{}", driver(
        5, 
        35
      ));
      
      println!("TEST-7...{}", driver(
        75, 
        525
      ));
      
      println!("TEST-8...{}", driver(
        85, 
        595
      ));
      
      println!("TEST-9...{}", 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 );
  }