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