80 lines
1.7 KiB
Markdown
80 lines
1.7 KiB
Markdown
---
|
|
id: 5900f3761000cf542c50fe89
|
|
challengeType: 5
|
|
title: 'Problem 10: Summation of primes'
|
|
---
|
|
|
|
## Description
|
|
<section id='description'>
|
|
The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.
|
|
Find the sum of all the primes below n.
|
|
</section>
|
|
|
|
## Instructions
|
|
<section id='instructions'>
|
|
|
|
</section>
|
|
|
|
## Tests
|
|
<section id='tests'>
|
|
|
|
```yml
|
|
tests:
|
|
- text: <code>primeSummation(17)</code> should return 41.
|
|
testString: assert.strictEqual(primeSummation(17), 41, '<code>primeSummation(17)</code> should return 41.');
|
|
- text: <code>primeSummation(2001)</code> should return 277050.
|
|
testString: assert.strictEqual(primeSummation(2001), 277050, '<code>primeSummation(2001)</code> should return 277050.');
|
|
- text: <code>primeSummation(140759)</code> should return 873608362.
|
|
testString: assert.strictEqual(primeSummation(140759), 873608362, '<code>primeSummation(140759)</code> should return 873608362.');
|
|
- text: <code>primeSummation(2000000)</code> should return 142913828922.
|
|
testString: assert.strictEqual(primeSummation(2000000), 142913828922, '<code>primeSummation(2000000)</code> should return 142913828922.');
|
|
|
|
```
|
|
|
|
</section>
|
|
|
|
## Challenge Seed
|
|
<section id='challengeSeed'>
|
|
|
|
<div id='js-seed'>
|
|
|
|
```js
|
|
function primeSummation(n) {
|
|
// Good luck!
|
|
return true;
|
|
}
|
|
|
|
primeSummation(2000000);
|
|
```
|
|
|
|
</div>
|
|
|
|
</section>
|
|
|
|
## Solution
|
|
<section id='solution'>
|
|
|
|
```js
|
|
//noprotect
|
|
function primeSummation(n) {
|
|
if (n < 3) { return 0 };
|
|
let nums = [0, 0, 2];
|
|
for (let i = 3; i < n; i += 2){
|
|
nums.push(i);
|
|
nums.push(0);
|
|
}
|
|
let sum = 2;
|
|
for (let i = 3; i < n; i += 2){
|
|
if (nums[i] !== 0){
|
|
sum += nums[i];
|
|
for (let j = i*i; j < n; j += i){
|
|
nums[j] = 0;
|
|
}
|
|
}
|
|
}
|
|
return sum;
|
|
}
|
|
```
|
|
|
|
</section>
|