solution: Project Euler 35 #1201

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	/**
	* Problem 35 - Circular primes
	*
	* @see {@link https://projecteuler.net/problem=35}
	*
	* The number, 197, is called a circular prime because all rotations of the digits: 197, 971, and 719, are themselves prime.
	* There are thirteen such primes below 100: 2, 3, 5, 7, 11, 13, 17, 31, 37, 71, 73, 79, and 97.
	* How many circular primes are there below one million?
	*
	* @author ddaniel27
	*/
	import { sieveOfEratosthenes } from '../Maths/SieveOfEratosthenesIntArray'

	function problem35 (n) {
	if (n < 2) {
	throw new Error('Invalid input')
	}
	const list = sieveOfEratosthenes(n).filter(prime => !prime.toString().match(/[024568]/)) // Get a list of primes without 0, 2, 4, 5, 6, 8

	const result = list.filter((number, _idx, arr) => {
	const str = String(number)
	for (let i = 0; i < str.length; i++) { // Get all rotations of the number
	const rotation = str.slice(i) + str.slice(0, i)
	if (!arr.includes(Number(rotation))) { // Check if the rotation is prime
	return false
	}
	}
	return true // If all rotations are prime, then the number is circular prime
	})

	return result.length + 1 // Add 2 to the result because 2 is a circular prime
	}

	export { problem35 }

18 changes: 18 additions & 0 deletions Project-Euler/test/Problem035.test.js

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	import { problem35 } from '../Problem035.js'

	describe('checking circular primes', () => {
	it('should be invalid input if number is negative', () => {
	expect(() => problem35(-3)).toThrowError('Invalid input')
	})
	it('should be invalid input if number is 0', () => {
	expect(() => problem35(0)).toThrowError('Invalid input')
	})
	// Project Euler Condition Check
	test('if the number is equal to 100 result should be 13', () => {
	expect(problem35(100)).toBe(13)
	})
	// Project Euler Challenge Check
	test('if the number is equal to one million result should be 55', () => {
	expect(problem35(1000000)).toBe(55)
	})
	})

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