2.4 KiB
2.4 KiB
title | id | challengeType | forumTopicId |
---|---|---|---|
Abundant, deficient and perfect number classifications | 594810f028c0303b75339acd | 5 | 302221 |
Description
n
where proper divisors are all positive integers n
other than n
itself.
If P(n) < n
then n
is classed as deficient
If P(n) === n
then n
is classed as perfect
If P(n) > n
then n
is classed as abundant
Example:
6
has proper divisors of 1
, 2
, and 3
.
1 + 2 + 3 = 6
, so 6
is classed as a perfect number.
Instructions
1
to 20,000
(inclusive) are in each of the three classes. Output the result as an array in the following format [deficient, perfect, abundant]
.
Tests
tests:
- text: <code>getDPA</code> should be a function.
testString: assert(typeof getDPA === 'function');
- text: <code>getDPA</code> should return an array.
testString: assert(Array.isArray(getDPA(100)));
- text: <code>getDPA</code> return value should have a length of 3.
testString: assert(getDPA(100).length === 3);
- text: <code>getDPA(20000)</code> should equal [15043, 4, 4953]
testString: assert.deepEqual(getDPA(20000), solution);
Challenge Seed
function getDPA(num) {
}
After Test
const solution = [15043, 4, 4953];
Solution
function getDPA(num) {
const dpa = [1, 0, 0];
for (let n = 2; n <= num; n += 1) {
let ds = 1;
const e = Math.sqrt(n);
for (let d = 2; d < e; d += 1) {
if (n % d === 0) {
ds += d + (n / d);
}
}
if (n % e === 0) {
ds += e;
}
dpa[ds < n ? 0 : ds === n ? 1 : 2] += 1;
}
return dpa;
}