Last active
December 17, 2015 08:19
-
-
Save bl4de/5579388 to your computer and use it in GitHub Desktop.
Siege of Eratostenes - JavaScript algorithm (working :P )
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <meta charset="utf-8" /> | |
| </head> | |
| <body> | |
| <div id="siege"></div> | |
| <script> | |
| // siege of Eratostenes | |
| // | |
| // other methods: http://www.wikihow.com/Check-if-a-Number-Is-Prime | |
| // | |
| // bl4de bloorq@gmail.com | |
| var SCOPE = 100000, | |
| arr = [], | |
| primes = [], | |
| i = 0, | |
| first = 2; | |
| for ( i; i < SCOPE; i++ ) { | |
| arr[i] = first++; | |
| } | |
| var min = arr[0]; | |
| console.time("siege"); | |
| while ( min < Math.sqrt( SCOPE ) ) { | |
| i = 0; | |
| console.log("delete all multiple of " + min); | |
| for (i; i < SCOPE; i++ ) { | |
| if ( arr[i] != min && arr[i] % min === 0 ) { | |
| arr[i] = 0; | |
| } | |
| } | |
| // next min | |
| for ( i =0; i < SCOPE; i++ ) { | |
| if ( arr[i] > min ) { | |
| min = arr[i]; | |
| break; | |
| } | |
| } | |
| } | |
| console.timeEnd("siege"); | |
| for ( i =0 ; i < arr.length; i++) { | |
| if (arr[i] > 0) { | |
| primes.push( arr[i] ); | |
| } | |
| } | |
| var siege = document.getElementById("siege"); | |
| siege.innerHTML = primes.toString(); | |
| </script> | |
| </body> | |
| </html> |
Author
Author
But it can be optimalized, I'm sure
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Result: 2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,101,103,107,109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,193,197,199,211,223,227,229,233,239,241,251,257,263,269,271,277,281,283,293,307,311,313,317,331,337,347,349,353,359,367,373,379,383,389,397,401,409,419,421,431,433,439,443,449,457,461,463,467,479,487,491,499,503,509,521,523,541,547,557,563,569,571,577,587,593,599,601,607,613,617,619,631,641,643,647,653,659,661,673,677,683,691,701,709,719,727,733,739,743,751,757,761,769,773,787,797,809,811,821,823,827,829,839,853,857,859,863,877,881,883,887,907,911,919,929,937,941,947,953,967,971,977,983,991,997