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  1. #include <iostream>
  2. #include <ctime>
  3. #include <cstdlib>
  4.  
  5. using namespace std;
  6.  
  7. #define N 100
  8.  
  9. void mult1(int **a, int **b, int **c)
  10. {
  11. 	for (unsigned q=0; q<N; ++q)
  12. 		for (unsigned w=0; w<N; ++w)
  13. 			c[q][w] = 0;
  14.  
  15. 	for (unsigned q=0; q<N; ++q)
  16. 		for (unsigned w=0; w<N; ++w)
  17. 			for (unsigned e=0; e<N; ++e)
  18. 				c[q][w] += a[q][e] * b[e][w];
  19. }
  20.  
  21. void mult2(int **a, int **b, int **c)
  22. {
  23. 	for (unsigned q=0; q<N; ++q)
  24. 		for (unsigned w=0; w<N; ++w)
  25. 			c[q][w] = 0;
  26.  
  27. 	for (unsigned q=0; q<N; ++q)
  28. 		for (unsigned w=0; w<N; ++w)
  29. 			for (unsigned e=0; e<N; ++e)
  30. 				c[q][w] += a[q][e] * b[w][e];
  31. }
  32.  
  33. void mult3(int **a, int **b, int **c)
  34. {
  35. 	for (unsigned q=0; q<N; ++q)
  36. 		for (unsigned w=0; w<N; ++w)
  37. 			c[q][w] = 0;
  38.  
  39. 	for (unsigned q=0; q<N; ++q)
  40. 	{
  41. 		int *aa = a[q];
  42. 		for (unsigned w=0; w<N; ++w)
  43. 		{
  44. 			int *bb = b[q];
  45. 			for (unsigned e=0; e<N; ++e)
  46. 				c[q][w] += aa[e] * bb[e];
  47. 		}
  48. 	}
  49. }
  50.  
  51. int main()
  52. {
  53. 	int **a = new int*[N];
  54. 	int **b = new int*[N];
  55. 	int **c = new int*[N];
  56.  
  57. 	for (unsigned q=0; q<N; ++q)
  58. 	{
  59. 		a[q] = new int[N];
  60. 		b[q] = new int[N];
  61. 		c[q] = new int[N];
  62.  
  63. 		for (unsigned w=0; w<N; ++w)
  64. 		{
  65. 			a[q][w] = rand();
  66. 			b[q][w] = rand();
  67. 		}
  68. 	}
  69.  
  70. 	long m1=0, m2=0, m3=0;
  71.  
  72. 	for (unsigned q=0; q<10; ++q)
  73. 	{
  74. 		long t = clock();
  75. 		mult1(a, b, c);
  76. 		m1 += t = clock() - t;
  77. 		cout << "1: " << t << endl;
  78.  
  79. 		t = clock();
  80. 		mult2(a, b, c);
  81. 		m2 += t = clock() - t;
  82. 		cout << "2: " << t << endl;
  83.  
  84. 		t = clock();
  85. 		mult3(a, b, c);
  86. 		m3 += t = clock() - t;
  87. 		cout << "3: " << t << endl;
  88. 	}
  89.  
  90. 	cout << endl << "Results: " << m1 << ", " << m2 << ", " << m3 << endl;
  91.  
  92. 	return 0;
  93. }
Success #stdin #stdout 0.02s 3472KB
comments (?)
stdin 
Standard input is empty
stdout 
1: 822
2: 769
3: 787
1: 816
2: 774
3: 785
1: 814
2: 713
3: 687
1: 720
2: 681
3: 743
1: 788
2: 661
3: 658
1: 700
2: 661
3: 705
1: 743
2: 674
3: 659
1: 740
2: 661
3: 669
1: 769
2: 662
3: 668
1: 699
2: 661
3: 732

Results: 7611, 6917, 7093
https://ideone.com/QoW7x9
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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