Add Problem4 (Largest Palindrome Product) #751

Original file line number	Diff line number	Diff line change
		@@ -1,46 +1,30 @@
	// https://projecteuler.net/problem=4
	/* A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 ×ばつ 99.
	Find the largest palindrome made from the product of two 3-digit numbers.
	*/
	const largestPalindromic = (digits) => {
	let i
	let n
	let m
	let d
	let limit
	let number = 0
	function isPalindrome (number) {
Copy link Member @raklaptudirm raklaptudirm Oct 7, 2021 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. Please add comments with a link to the problem.
	// just 2 random names for variables!
	const look = String(number)
	let hear = false

	for (i = 1; i < digits; i++) {
	number = 10 * number + 9
	}
	const inf = number // highest (digits - 1) number, in this example highest 2 digit number
	const sup = 10 * number + 9 // highest (digits) number, in this example highest 3 digit number

	const isPalindromic = (n) => {
	let p = 0
	const q = n
	let r
	while (n > 0) {
	r = n % 10
	p = 10 * p + r
	n = Math.floor(n / 10)
	for (let i = 0; i < look.length; i++) {
	if (look[i] === look[(look.length) - (i + 1)]) {
	hear = true
	} else {
	return false
		}
	return p === q // returning whether the number is palindromic or not
		}
	return hear
	}

	function largestPalindromeProduct (n) {
	let product = 0
	let largestPalindrome = 11

	for (n = sup * sup, m = inf * inf; n > m; n--) {
	if (isPalindromic(n)) {
	limit = Math.ceil(Math.sqrt(n))
	d = sup
	while (d >= limit) {
	if (n % d === 0 && n / d > inf) {
	return n
	}
	d -= 1
	}
	for (let i = 10 (n - 1); i < 10 n; i++) {
	for (let j = 10 (n - 1); j < 10 n; j++) {
	product = i * j
	if (isPalindrome(product) && product > largestPalindrome) { largestPalindrome = product }
		}
		}
	return NaN// returning not a number, if any such case arise
	return largestPalindrome
		}

	console.log(largestPalindromic(3))
	console.log(isPalindrome(9009))
Copy link Member @raklaptudirm raklaptudirm Oct 7, 2021 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. I know the original function console logged, but it will be better if you remove the console logs and add jest tests instead.
	console.log(largestPalindromeProduct(2))

Navigation Menu

Search code, repositories, users, issues, pull requests...

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Uh oh!

Add Problem4 (Largest Palindrome Product) #751

Uh oh!

Add Problem4 (Largest Palindrome Product) #751

Filter by extension

Uh oh!

Uh oh!

Diff view

Diff view

There are no files selected for viewing

@raklaptudirm raklaptudirm Oct 7, 2021

Choose a reason for hiding this comment

Uh oh!

@raklaptudirm raklaptudirm Oct 7, 2021

Choose a reason for hiding this comment

Uh oh!