73 lines
1.1 KiB
Markdown
73 lines
1.1 KiB
Markdown
---
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id: 5900f4ab1000cf542c50ffbe
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challengeType: 5
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videoUrl: ''
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title: 问题319：有界序列
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---
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## Description
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<section id="description">
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令x1，x2，...，xn为长度为n的序列，使得：
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x1 = 2
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对于所有1 <i≤n：xi-1 <xi
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对于所有1≤i，j≤n的i和j：（xi）j <（xj + 1）i
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这样的长度为2的序列只有五个，即：
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{2,4}，{2,5}，{2,6}，{2,7}和{2,8}。
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有293个这样的长度为5的序列。 以下是三个示例：
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{2,5,11,25,55}，{2,6,14,36,88}，{2,8,22,64,181}。
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令t（n）表示长度为n的此类序列的数量。
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给出t（10）= 86195和t（20）= 5227991891。
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找出t（1010）并给出答案模块109。
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</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>euler319()</code>应该返回268457129。
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testString: assert.strictEqual(euler319(), 268457129);
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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 euler319() {
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// Good luck!
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return true;
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}
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euler319();
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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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