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  1. #include <iostream>
  2. #include <ctime>
  3. #include <cstdint>
  4. using std::cout;
  5. using std::endl;
  6.  
  7. std::uint32_t rand_value;
  8.  
  9. std::uint32_t lcg()
  10. {
  11. 	const auto a = 22695477u;
  12. 	const auto c = 1u;
  13.  
  14. 	rand_value = a * rand_value + c;
  15. 	return rand_value;
  16. }
  17.  
  18. enum func_method {log_or, mult};
  19.  
  20. template <typename test_type, func_method method>
  21. void test_func()
  22. {
  23. 	const unsigned long end = 800'000'000;
  24. 	unsigned int sum = 0;
  25.  
  26. 	std::uint32_t mask = 32767;
  27.  
  28. 	auto clock_begin = std::clock();
  29. 	if (method == func_method::log_or)
  30. 		for (unsigned long i = 0; i < end; ++i)
  31. 		{
  32. 			test_type a = lcg() & mask;
  33. 			test_type b = lcg() & mask;
  34. 			if (a == 0 || b == 0)
  35. 				++sum;
  36. 		}
  37. 	else if (method == func_method::mult)
  38. 		for (unsigned long i = 0; i < end; ++i)
  39. 		{
  40. 			test_type a = lcg() & mask;
  41. 			test_type b = lcg() & mask;
  42. 			if (a * b == 0)
  43. 				++sum;
  44. 		}
  45. 	else
  46. 		cout << "Invalid method" << endl;
  47. 	auto clock_end = std::clock();
  48.  
  49. 	cout << "sum:  " << sum << endl;
  50. 	cout << "time: " << double(clock_end - clock_begin) / CLOCKS_PER_SEC << endl;
  51. }
  52.  
  53. int main()
  54. {
  55. 	typedef int test_type;
  56.  
  57. 	rand_value = 1;
  58. 	test_func<test_type, func_method::mult>();
  59. 	rand_value = 1;
  60. 	test_func<test_type, func_method::log_or>();
  61.  
  62. 	return 0;
  63. }
Success #stdin #stdout 4.6s 5048KB
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stdin
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Standard input is empty
stdout
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sum:  48828
time: 2.22886
sum:  48828
time: 2.36976
https://ideone.com/EwYuK9
language:
C++14 (clang 8.0)
created:
4 years ago
visibility:
public

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