74 lines
1.2 KiB
Markdown
74 lines
1.2 KiB
Markdown
---
|
||
id: 5900f3761000cf542c50fe89
|
||
title: 问题10：素数的总和
|
||
challengeType: 5
|
||
videoUrl: ''
|
||
dashedName: problem-10-summation-of-primes
|
||
---
|
||
|
||
# --description--
|
||
|
||
低于10的素数之和为2 + 3 + 5 + 7 = 17.求出n以下所有素数的总和。
|
||
|
||
# --hints--
|
||
|
||
`primeSummation(17)`应该返回41。
|
||
|
||
```js
|
||
assert.strictEqual(primeSummation(17), 41);
|
||
```
|
||
|
||
`primeSummation(2001)`应该返回277050。
|
||
|
||
```js
|
||
assert.strictEqual(primeSummation(2001), 277050);
|
||
```
|
||
|
||
`primeSummation(140759)`应该返回873608362。
|
||
|
||
```js
|
||
assert.strictEqual(primeSummation(140759), 873608362);
|
||
```
|
||
|
||
`primeSummation(2000000)`应返回142913828922。
|
||
|
||
```js
|
||
assert.strictEqual(primeSummation(2000000), 142913828922);
|
||
```
|
||
|
||
# --seed--
|
||
|
||
## --seed-contents--
|
||
|
||
```js
|
||
function primeSummation(n) {
|
||
|
||
return true;
|
||
}
|
||
|
||
primeSummation(2000000);
|
||
```
|
||
|
||
# --solutions--
|
||
|
||
```js
|
||
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;
|
||
}
|
||
```
|