Add LinearSieve.js #828

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	const LinearSieve = (n) => {
	/*
	* Calculates prime numbers till a number n
	* Time Complexity: O(n)
	* Explanation: https://cp-algorithms.com/algebra/prime-sieve-linear.html
	* :param n: Number up to which to calculate primes
	* :return: A list containing only primes
	*/
	const isnPrime = new Array(n + 1)
	isnPrime[0] = isnPrime[1] = true
	const primes = []
	for (let i = 2; i <= n; i++) {
	if (!isnPrime[i]) primes.push(i)
	for (const p of primes) {
	const k = i * p
	if (k > n) break
	isnPrime[k] = true
	if (i % p === 0) break
	}
	}
	return primes
	}

	export { LinearSieve }

16 changes: 16 additions & 0 deletions Maths/test/LinearSieve.test.js

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	import { LinearSieve } from '../LinearSieve'
	import { PrimeCheck } from '../PrimeCheck'

	describe('LinearSieve', () => {
	it('should return primes below 100', () => {
	expect(LinearSieve(100)).toEqual([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])
	})

	it('should return primes only', () => {
	const n = 100000
	const primes = LinearSieve(n)
	for (const p of primes) {
	expect(PrimeCheck(p)).toBeTruthy()
	}
	})
	})

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