2.3 KiB
2.3 KiB
id | localeTitle | challengeType | title |
---|---|---|---|
5 | 5900f3811000cf542c50fe94 | 5 | Problem 21: Amicable numbers |
Description
Instructions
Tests
tests:
- text: <code>sumAmicableNum(1000)</code> debe devolver 504.
testString: 'assert.strictEqual(sumAmicableNum(1000), 504, "<code>sumAmicableNum(1000)</code> should return 504.");'
- text: <code>sumAmicableNum(2000)</code> debe devolver 2898.
testString: 'assert.strictEqual(sumAmicableNum(2000), 2898, "<code>sumAmicableNum(2000)</code> should return 2898.");'
- text: <code>sumAmicableNum(5000)</code> debe devolver 8442.
testString: 'assert.strictEqual(sumAmicableNum(5000), 8442, "<code>sumAmicableNum(5000)</code> should return 8442.");'
- text: <code>sumAmicableNum(10000)</code> debe devolver 31626.
testString: 'assert.strictEqual(sumAmicableNum(10000), 31626, "<code>sumAmicableNum(10000)</code> should return 31626.");'
Challenge Seed
function sumAmicableNum(n) {
// Good luck!
return n;
}
sumAmicableNum(10000);
Solution
const sumAmicableNum = (n) => {
const fsum = (n) => {
let sum = 1;
for (let i = 2; i <= Math.floor(Math.sqrt(n)); i++)
if (Math.floor(n % i) === 0)
sum += i + Math.floor(n / i);
return sum;
};
let d = [];
let amicableSum = 0;
for (let i=2; i<n; i++) d[i] = fsum(i);
for (let i=2; i<n; i++) {
let dsum = d[i];
if (d[dsum]===i && i!==dsum) amicableSum += i+dsum;
}
return amicableSum/2;
};