1.6 KiB
1.6 KiB
id | title | challengeType | forumTopicId | dashedName |
---|---|---|---|---|
5900f36f1000cf542c50fe82 | Problem 3: Largest prime factor | 5 | 301952 | problem-3-largest-prime-factor |
--description--
The prime factors of 13195 are 5, 7, 13 and 29.
What is the largest prime factor of the given number
?
--hints--
largestPrimeFactor(2)
should return a number.
assert(typeof largestPrimeFactor(2) === 'number');
largestPrimeFactor(2)
should return 2.
assert.strictEqual(largestPrimeFactor(2), 2);
largestPrimeFactor(3)
should return 3.
assert.strictEqual(largestPrimeFactor(3), 3);
largestPrimeFactor(5)
should return 5.
assert.strictEqual(largestPrimeFactor(5), 5);
largestPrimeFactor(7)
should return 7.
assert.strictEqual(largestPrimeFactor(7), 7);
largestPrimeFactor(8)
should return 2.
assert.strictEqual(largestPrimeFactor(8), 2);
largestPrimeFactor(13195)
should return 29.
assert.strictEqual(largestPrimeFactor(13195), 29);
largestPrimeFactor(600851475143)
should return 6857.
assert.strictEqual(largestPrimeFactor(600851475143), 6857);
--seed--
--seed-contents--
function largestPrimeFactor(number) {
return true;
}
largestPrimeFactor(13195);
--solutions--
const largestPrimeFactor = (number) => {
let largestFactor = number;
for (let i = 2; i <= Math.sqrt(largestFactor); i++) {
if (!(largestFactor % i)) {
let factor = largestFactor / i;
let candidate = largestPrimeFactor(factor);
return i > candidate ? i : candidate;
}
}
return largestFactor;
}