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  1. #include <iostream>
  2. #include <vector>
  3. #include <chrono>
  4. #include <array>
  5. using namespace std;
  6.  
  7.  
  8. struct  float2
  9. {
  10.     float x, y ;
  11. };
  12.  
  13. float2 make_float2(float x, float y) {
  14.  
  15. 	return float2{x, y};
  16.  
  17. }
  18.  
  19. void originalMethod() {
  20. 		std::vector<std::vector<float>> pts;
  21. 	for (int val = 0; val < 10000; ++val) {
  22. 		std::vector<float> p1{float(val),float(val+1)};
  23. 		pts.push_back(p1);
  24. 	}
  25.  
  26. 	auto start = chrono::steady_clock::now();
  27. 	std::vector<float2> lattice;
  28. 	lattice.reserve(pts.size());
  29. 	for (auto p : pts){
  30.                 lattice.emplace_back(make_float2(p[0],p[1]));
  31.             }
  32. 	auto end = chrono::steady_clock::now();
  33. 	auto diff = end - start;
  34. 	cout << chrono::duration <double, nano> (diff).count() << " ns" << endl;
  35. }
  36.  
  37. void newMethod() {
  38. 	std::vector<std::array<float, 2>> pts;
  39. 	for (int val = 0; val < 10000; ++val) {
  40. 		std::array<float, 2> p1{float(val),float(val+1)};
  41. 		pts.push_back(p1);
  42. 	}
  43.  
  44. 	auto start = chrono::steady_clock::now();
  45. 	std::vector<float2> lattice;
  46. 	for (auto p : pts){
  47. 	    if (p.size() == 2) {
  48.             	float2 p_ = make_float2(p[0],p[1]);
  49.             	lattice.push_back(p_);
  50. 	    }
  51.  
  52. 	}
  53. 	auto end = chrono::steady_clock::now();
  54. 	auto diff = end - start;
  55. 	cout << chrono::duration <double, nano> (diff).count() << " ns" << endl;
  56. }
  57.  
  58.  
  59. int main() {
  60.  
  61. 	originalMethod();
  62. 	newMethod();
  63. 	// your code goes here
  64. 	return 0;
  65. }
Success #stdin #stdout 0s 4508KB
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Standard input is empty
stdout
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519839 ns
110164 ns
https://ideone.com/37JfqB
language:
C++ (gcc 8.3)
created:
6 years ago
visibility:
public

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