2018-10-10 18:03:03 -04:00
|
|
|
|
---
|
|
|
|
|
id: 5900f4ab1000cf542c50ffbd
|
|
|
|
|
challengeType: 5
|
|
|
|
|
videoUrl: ''
|
2020-10-01 17:54:21 +02:00
|
|
|
|
title: 问题318:2011个九
|
2018-10-10 18:03:03 -04:00
|
|
|
|
---
|
|
|
|
|
|
|
|
|
|
## Description
|
2020-02-18 01:40:55 +09:00
|
|
|
|
<section id="description">
|
|
|
|
|
考虑实数√2+√3。
|
|
|
|
|
当我们计算√2+√3的偶数幂时
|
|
|
|
|
我们得到:
|
|
|
|
|
(√2+√3)2 = 9.898979485566356 ...
|
|
|
|
|
(√2+√3)4 = 97.98979485566356 ...
|
|
|
|
|
(√2+√3)6 = 969.998969071069263 ...
|
|
|
|
|
(√2+√3)8 = 9601.99989585502907 ...
|
|
|
|
|
(√2+√3)10 = 95049.999989479221 ...
|
|
|
|
|
(√2+√3)12 = 940897.9999989371855 ...
|
|
|
|
|
(√2+√3)14 = 9313929.99999989263 ...
|
|
|
|
|
(√2+√3)16 = 92198401.99999998915 ...
|
|
|
|
|
|
|
|
|
|
这些幂的小数部分开头的连续九个数字似乎没有减少。
|
|
|
|
|
实际上,可以证明(√2+√3)2n的小数部分对于大n接近1。
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
考虑形式为√p+√q的所有实数,其中p和q为正整数,且p <q,使得小数部分
|
|
|
|
|
(√p+√q)的2n对于大n接近1。
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
令C(p,q,n)为(√p+√q)2n的小数部分开头的连续九个数字。
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
令N(p,q)为n的最小值,以使C(p,q,n)≥2011。
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
求p + q≤2011的∑N(p,q)。
|
|
|
|
|
</section>
|
2018-10-10 18:03:03 -04:00
|
|
|
|
|
|
|
|
|
## Instructions
|
2020-02-18 01:40:55 +09:00
|
|
|
|
<section id="instructions">
|
|
|
|
|
</section>
|
2018-10-10 18:03:03 -04:00
|
|
|
|
|
|
|
|
|
## Tests
|
|
|
|
|
<section id='tests'>
|
|
|
|
|
|
|
|
|
|
```yml
|
|
|
|
|
tests:
|
2020-02-18 01:40:55 +09:00
|
|
|
|
- text: <code>euler318()</code>应该返回709313889。
|
|
|
|
|
testString: assert.strictEqual(euler318(), 709313889);
|
2018-10-10 18:03:03 -04:00
|
|
|
|
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
</section>
|
|
|
|
|
|
|
|
|
|
## Challenge Seed
|
|
|
|
|
<section id='challengeSeed'>
|
|
|
|
|
|
|
|
|
|
<div id='js-seed'>
|
|
|
|
|
|
|
|
|
|
```js
|
|
|
|
|
function euler318() {
|
|
|
|
|
// Good luck!
|
|
|
|
|
return true;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
euler318();
|
|
|
|
|
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
</div>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
</section>
|
|
|
|
|
|
|
|
|
|
## Solution
|
|
|
|
|
<section id='solution'>
|
|
|
|
|
|
|
|
|
|
```js
|
|
|
|
|
// solution required
|
|
|
|
|
```
|
2020-08-13 17:24:35 +02:00
|
|
|
|
|
|
|
|
|
/section>
|