diff --git a/Project-Euler/Problem035.js b/Project-Euler/Problem035.js new file mode 100644 index 0000000000..b62a8f0312 --- /dev/null +++ b/Project-Euler/Problem035.js @@ -0,0 +1,34 @@ +/** + * 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 } diff --git a/Project-Euler/test/Problem035.test.js b/Project-Euler/test/Problem035.test.js new file mode 100644 index 0000000000..ebaa4ac46f --- /dev/null +++ b/Project-Euler/test/Problem035.test.js @@ -0,0 +1,18 @@ +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) + }) +})