Created
November 13, 2010 13:19
-
-
Save think49/675313 to your computer and use it in GitHub Desktop.
isPrime.js : 素数を判定する / get-primes.js : 素数リストを出力する
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
| /** | |
| * get-primes.js | |
| * Get a prime list. | |
| * | |
| * @version 1.0.1 | |
| * @author think49 | |
| * @url https://gist.github.com/675313 | |
| * @license http://www.opensource.org/licenses/mit-license.php (The MIT License) | |
| */ | |
| function getPrimes (length) { | |
| var i, number, primes, prime, perfectPower, primeLength; | |
| /** Check a natural number */ | |
| if (length < 1 || length % 1 !== 0) { | |
| return []; | |
| } | |
| primes = [2]; | |
| primeLength = primes.length; | |
| number = 3; | |
| /** Eratosthenes' sieve */ | |
| while (length > primeLength) { | |
| i = 0; | |
| do { | |
| prime = primes[i++]; | |
| perfectPower = prime * prime; | |
| } while (number > perfectPower && number % prime !== 0); | |
| if (number < perfectPower) { | |
| primeLength = primes.push(number); | |
| } | |
| number += 2; | |
| } | |
| return primes; | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
コードの整理に LabelledStatement を使いました。
コメントに JSDoc を使いました。
素数判定に下記の定理を使いました。
TagIndexで回答しました。