70 lines
2.1 KiB
Java
70 lines
2.1 KiB
Java
/*
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This is a Java Program to Implement Sieve Of Eratosthenes Algorithm. This is a program to find all primes less than a number.
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*/
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/**
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** Java Program to implement Sieve Of Eratosthenes
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**/
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import java.util.Scanner;
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/** Class SieveOfEratosthenes **/
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public class SieveOfEratosthenes
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{
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/** Function to calculate all primes less than n **/
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private int[] calcPrimes(int N)
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{
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int[] arr = new int[N + 1];
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for (int i = 2; i <= Math.sqrt(N); i++)
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{
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if (arr[i] == 0)
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{
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for (int j = i * i; j <= N; j += i)
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{
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arr[j] = 1;
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}
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}
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}
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return arr;
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}
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/** Function to get all primes **/
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public void getPrimes(int N)
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{
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int[] primes = calcPrimes(N);
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display(primes);
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}
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/** Function to display all primes **/
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public void display(int[] primes)
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{
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System.out.print("\nPrimes = ");
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for (int i = 2; i < primes.length; i++)
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if (primes[i] == 0)
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System.out.print(i +" ");
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System.out.println();
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}
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/** Main function **/
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public static void main (String[] args)
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{
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Scanner scan = new Scanner(System.in);
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System.out.println("Sieve Of Eratosthenes Prime Algorithm Test\n");
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/** Make an object of SieveOfEratosthenes class **/
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SieveOfEratosthenes soe = new SieveOfEratosthenes();
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/** Accept n **/
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System.out.println("Enter number to find all primes less than the number\n");
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int n = scan.nextInt();
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soe.getPrimes(n);
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}
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}
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/*
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Enter number to find all primes less than the number
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500
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Primes = 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97
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101 103 107 109 113 127 131 137 139 149 151 157 163 167 173 179 181 191 193 197
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199 211 223 227 229 233 239 241 251 257 263 269 271 277 281 283 293 307 311 313
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317 331 337 347 349 353 359 367 373 379 383 389 397 401 409 419 421 431 433 439
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443 449 457 461 463 467 479 487 491 499
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