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a62a46e732
* remove intarr test * Remove main file oops * FIXES: #1666 , remove references to SieveOfEratosthenesIntArray * Finally fix the requirements, passes vitest * Updated Documentation in README.md * FIXES: #1666 and conform to alg comment standards --------- Co-authored-by: SpiderMath <SpiderMath@users.noreply.github.com>
40 lines
1.3 KiB
JavaScript
40 lines
1.3 KiB
JavaScript
/**
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* Problem 35 - Circular primes
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*
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* @see {@link https://projecteuler.net/problem=35}
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*
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* The number, 197, is called a circular prime because all rotations of the digits: 197, 971, and 719, are themselves prime.
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* There are thirteen such primes below 100: 2, 3, 5, 7, 11, 13, 17, 31, 37, 71, 73, 79, and 97.
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* How many circular primes are there below one million?
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*
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* @author ddaniel27
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*/
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import { sieveOfEratosthenes } from '../Maths/SieveOfEratosthenes'
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function problem35(n) {
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if (n < 2) {
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throw new Error('Invalid input')
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}
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// Get a list of primes without 0, 2, 4, 5, 6, 8; this discards the circular primes 2 & 5
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const list = sieveOfEratosthenes(n).filter(
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(prime) => !prime.toString().match(/[024568]/)
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)
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const result = list.filter((number, _idx, arr) => {
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const str = String(number)
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for (let i = 0; i < str.length; i++) {
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// Get all rotations of the number
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const rotation = str.slice(i) + str.slice(0, i)
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if (!arr.includes(Number(rotation))) {
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// Check if the rotation is prime
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return false
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}
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}
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return true // If all rotations are prime, then the number is circular prime
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})
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return result.length + 2 // Add 2 to the result because the circular primes 2 & 5 were discarded
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}
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export { problem35 }
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