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  1. class  Main {
  2. 	public static void main(String[] args) {
  3.  
  4. 		//Case 1 comparing Algorithms
  5. 		long startTime = System.currentTimeMillis();  // Start Time
  6. 		for (int i = 2; i <= 100000; ++i){
  7. 			if (isPrime1(i)) continue;
  8. 		}
  9. 		long stopTime = System.currentTimeMillis();   // End Time
  10.         System.out.printf("Duracion: %4d ms. while (i*i <= N) Algorithm\n", stopTime - startTime);
  11.  
  12.         //Case 2 comparing Algorithms
  13. 		startTime = System.currentTimeMillis();
  14. 		for (int i = 2; i <= 100000; ++i){
  15. 			if (isPrime2(i)) continue;
  16. 		}
  17. 		stopTime = System.currentTimeMillis();
  18.         System.out.printf("Duracion: %4d ms. while (i <= sqrt(N)) Algorithm\n", stopTime - startTime);
  19.  
  20.         //Case 3 comparing Algorithms
  21. 		startTime = System.currentTimeMillis(); 
  22. 		for (int i = 2; i <= 100000; ++i){
  23. 			if (isPrime3(i)) continue;
  24. 		}
  25. 		stopTime = System.currentTimeMillis();  
  26.         System.out.printf("Duracion: %4d ms. s = sqrt(N) while (i <= s) Algorithm\n", stopTime - startTime);
  27.  
  28. 		//Case 4 comparing Algorithms
  29. 		startTime = System.currentTimeMillis();  
  30. 		for (int i = 2; i <= 100000; ++i){
  31. 			if (isPrime4(i)) continue;
  32. 		}
  33. 		stopTime = System.currentTimeMillis();
  34.         System.out.printf("Duracion: %4d ms. s = Math.sqrt(N) while (i <= s) Algorithm\n", stopTime - startTime);
  35.  
  36.      }
  37.  
  38. 	public static boolean isPrime1(int n)
  39. 	{
  40. 		for (long i = 2; i*i <= n; i++){
  41. 			if (n%i==0)
  42. 				return false;
  43. 		}
  44. 		return true;
  45. 	}
  46.  
  47. 	public static boolean isPrime2(int n)
  48. 	{
  49. 		for (long i = 2; i <= sqrt(n); i++){
  50. 			if (n%i==0)
  51. 				return false;
  52. 		}
  53. 		return true;
  54. 	}
  55.  
  56. 	public static boolean isPrime3(int n)
  57. 	{
  58. 		double s = sqrt(n);
  59. 		for (long i = 2; i <= s; i++){
  60. 			if (n%i==0)
  61. 				return false;
  62. 		}
  63. 		return true;
  64. 	}
  65. 	public static boolean isPrime4(int n)
  66. 	{
  67. 		//Proving wich if faster between my sqrt method or Java's sqrt
  68. 		double s = Math.sqrt(n);
  69. 		for (long i = 2; i <= s; i++){
  70. 			if (n%i==0)
  71. 				return false;
  72. 		}
  73. 		return true;
  74. 	}
  75. 	public static double abs(double n){
  76. 		return n < 0 ? -n : n;
  77. 	}
  78. 	public static double sqrt(double n)
  79. 	{
  80. 		//Newton's method, from book Algorithms 4th edition by Robert Sedgwick and Kevin Wayne
  81. 		if (n < 0) return Double.NaN;
  82.  
  83. 		double err = 1e-15;
  84. 		double p = n;
  85.  
  86. 		while (abs(p - n/p) > err * n)
  87. 			p = (p + n/p) / 2.0;
  88.  
  89. 		return p;
  90. 	}
  91. }
Success #stdin #stdout 1.42s 380352KB
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stdout
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Duracion:  106 ms. while (i*i <= N) Algorithm
Duracion:  943 ms. while (i <= sqrt(N)) Algorithm
Duracion:  164 ms. s = sqrt(N) while (i <= s) Algorithm
Duracion:  131 ms. s = Math.sqrt(N) while (i <= s) Algorithm
https://ideone.com/Fapj1P
language:
Java (12.0.1)
created:
10 years ago
visibility:
public

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