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  1. #include <iostream>
  2. #include <math.h>
  3. using namespace std;
  4.  
  5. #define MAX 1000000
  6. int snt[MAX+10];
  7. int mcd[MAX+10];
  8.  
  9. int sont(int n)
  10. {
  11. 	if (n<2)
  12. 		return 0;
  13. 	for (int i=2; i<=sqrt(n); i++)
  14. 	{
  15. 		if (n%i==0)
  16. 		{
  17. 			return 0;
  18. 		}
  19. 	}
  20. 	return 1;
  21. }
  22.  
  23. void init()
  24. {
  25. 	for (int i=1; i<=MAX; i++)
  26. 	{
  27. 		snt[i] = 1;
  28. 		mcd[i] = 0;
  29. 	}
  30. }
  31.  
  32. void sangnt()
  33. {
  34. 	snt[0] = 0;
  35. 	snt[1] = 0;
  36. 	for (int i=2; i<=sqrt(MAX); i++)
  37. 	{
  38. 		if (snt[i] == 1)
  39. 		{
  40. 			for (int j=2; j<=MAX/i; j++)
  41. 			{
  42. 				snt[i*j] = 0;
  43. 			}
  44. 		}
  45. 	}
  46. }
  47.  
  48.  
  49. int main()
  50. {
  51. 	init();
  52. 	sangnt();
  53. 	int t;
  54. 	cin>>t;
  55. 	while(t--)
  56. 	{
  57. 		int a, b;
  58. 		cin>>a>>b;
  59. 		int ts = 0;
  60. 		for (int i=a; i<=b; i++)
  61. 		{
  62. 			if (snt[i]==1 && snt[i+6]==1 && i+6<=b)
  63. 			{
  64. 				ts ++;
  65. 			}
  66. 		}
  67. 		cout<<ts<<endl;
  68. 	}
  69. 	return 0;
  70. }
Success #stdin #stdout 0.01s 11308KB
comments (?)
stdin
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3
11 19
6 59
2 1000000
stdout
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2
10
16386
https://ideone.com/vsJJaR
o- PTIT018A - ACM PTIT 2018 A - CẶP SỐ NGUYÊN TỐ ĐẶC BIỆT
language:
C++ (gcc 8.3)
created:
3 years ago
visibility:
secret

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