1.8 KiB
1.8 KiB
title | id | challengeType |
---|---|---|
Factors of an integer | 597f1e7fbc206f0e9ba95dc4 | 5 |
Description
Write a function that returns the factors of a positive integer.
These factors are the positive integers by which the number being factored can be divided to yield a positive integer result.
///Instructions
Tests
tests:
- text: <code>factors</code> is a function.
testString: assert(typeof factors === 'function', '<code>factors</code> is a function.');
- text: <code>factors(45)</code> should return <code>[1,3,5,9,15,45]</code>.
testString: assert.deepEqual(factors(45), ans[0], '<code>factors(45)</code> should return <code>[1,3,5,9,15,45]</code>.');
- text: <code>factors(53)</code> should return <code>[1,53]</code>.
testString: assert.deepEqual(factors(53), ans[1], '<code>factors(53)</code> should return <code>[1,53]</code>.');
- text: <code>factors(64)</code> should return <code>[1,2,4,8,16,32,64]</code>.
testString: assert.deepEqual(factors(64), ans[2], '<code>factors(64)</code> should return <code>[1,2,4,8,16,32,64]</code>.');
Challenge Seed
function factors (num) {
// Good luck!
}
After Test
const ans=[[1,3,5,9,15,45],[1,53],[1,2,4,8,16,32,64]];
Solution
function factors(num)
{
let n_factors = [], i, sqr=Math.floor(Math.sqrt(num));
for (i = 1; i <=sqr ; i += 1)
if (num % i === 0)
{
n_factors.push(i);
if (num / i !== i)
n_factors.push(num / i);
}
n_factors.sort(function(a, b){return a - b;});
return n_factors;
}