@dxzmpk/js-algorithms-data-structures
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Algorithms and data-structures implemented on JavaScript
37 lines (31 loc) • 986 B
JavaScript
/**
* @param {number} maxNumber
* @return {number[]}
*/
export default function sieveOfEratosthenes(maxNumber) {
const isPrime = new Array(maxNumber + 1).fill(true);
isPrime[0] = false;
isPrime[1] = false;
const primes = [];
for (let number = 2; number <= maxNumber; number += 1) {
if (isPrime[number] === true) {
primes.push(number);
/*
* Optimisation.
* Start marking multiples of `p` from `p * p`, and not from `2 * p`.
* The reason why this works is because, at that point, smaller multiples
* of `p` will have already been marked `false`.
*
* Warning: When working with really big numbers, the following line may cause overflow
* In that case, it can be changed to:
* let nextNumber = 2 * number;
*/
let nextNumber = number * number;
while (nextNumber <= maxNumber) {
isPrime[nextNumber] = false;
nextNumber += number;
}
}
}
return primes;
}