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  1. #include <iostream>
  2.  
  3. using namespace std;
  4.  
  5. //ham tinh can bac 2
  6. unsigned long my_sprt(unsigned long x)
  7. {
  8. 	unsigned long xn, xprev;
  9. 	xn = x/2;
  10. 	xprev = 0;
  11. 	while(xn !=xprev)
  12. 	{
  13. 		xprev = xn;
  14. 		xn = (xn + x/xprev)/2;
  15. 	}
  16. 	return xn;
  17. }
  18. //ham check xem so do co phai so nguyen to khong
  19. bool check_prime(int x)
  20. {
  21. 	if(x == 1 || x == 2)
  22. 		return true;
  23. 	for(int ii = 2; ii<x; ii++)
  24. 	{
  25. 		if((x % ii) == 0)
  26. 			return false;
  27. 	}
  28. 	return true;
  29. }
  30.  
  31. bool check_prime1(unsigned long x)
  32. {
  33. 	if(x == 1 || x == 2 || x == 3)
  34. 		return true;
  35. 	if(((x+1) % 6 == 0) || ((x - 1) % 6 == 0))
  36. 	{
  37. 		for(int ii = 2; ii <= my_sprt(x); ii++)
  38. 		{
  39. 			if((x % ii) == 0)
  40. 				return false; 
  41. 		}
  42. 		return true;
  43. 	}
  44. 	return false;
  45. }
  46.  
  47. int main(int argc, char** argv)
  48. {
  49. 	int T, test_case;
  50. 	unsigned long n, m;
  51. //	freopen("input.txt", "r", stdin);
  52.  
  53. 	cin >> T;
  54. 	for(test_case = 0; test_case  < T; test_case++)
  55. 	{
  56. 		cin >> n >> m;
  57. 		for(int j = n; j<=m; j++)
  58. 		{
  59. 			if(check_prime1(j))
  60. 				cout << j << endl;
  61. 		}
  62. 		// Print the answer to standard output(screen).
  63. 		//cout << "Case #" << test_case+1 << endl;
  64. 		cout << endl;
  65. 	}
  66.  
  67. 	return 0;//Your program should return 0 on normal termination.
  68. }
  69.  
Runtime error #stdin #stdout 0.17s 2688KB
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https://ideone.com/BZsfWc
language:
C++ 4.3.2 (gcc-4.3.2)
created:
7 years ago
visibility:
public

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