56 lines
1.1 KiB
Markdown
56 lines
1.1 KiB
Markdown
---
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id: 5900f4c41000cf542c50ffd6
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challengeType: 5
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videoUrl: ''
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localeTitle: 问题343：分数序列
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---
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## Description
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<section id="description">对于任何正整数k，分数xi / yi的有限序列ai由以下定义：a1 = 1 / k且ai =（xi-1 + 1）/（yi-1-1）减少到最低项i> 1 。当ai达到某个整数n时，序列停止。 （即，当yi = 1时。）定义f（k）= n。例如，对于k = 20： <p> 1/20→2/19→3/18 = 1/6→2/5→3/4→4/3→5/2→6/1 = 6 </p><p>所以f（20）= 6。 </p><p>对于1≤k≤100，f（1）= 1，f（2）= 2，f（3）= 1且Σf（k3）= 118937。 </p><p>找Σf（k3）为1≤k≤2×106。 </p></section>
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## Instructions
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<section id="instructions">
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: <code>euler343()</code>应该返回269533451410884200。
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testString: assert.strictEqual(euler343(), 269533451410884200);
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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function euler343() {
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// Good luck!
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return true;
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}
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euler343();
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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// solution required
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```
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/section>
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