88 lines
3.8 KiB
Markdown
88 lines
3.8 KiB
Markdown
---
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title: Hofstadter Figure-Figure sequences
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id: 59622f89e4e137560018a40e
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challengeType: 5
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videoUrl: ''
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localeTitle: Hofstadter图 - 图序列
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---
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## Description
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<section id="description"><p>这两个正整数序列定义为: </p><p> <big>$$ R(1)= 1 \; \ S(1)= 2 \\ R(n)= R(n-1)+ S(n-1),\ quad n> 1. $$</big> </p><p>序列<big>$ S(n)$</big>进一步定义为<big>$ R(n)$中</big>不存在的正整数序列。 </p><p>序列<big>$ R $</big>开始: </p><p> 1,3,7,12,18 ...... </p><p>序列<big>$ S $</big>开始: </p><p> 2,4,5,6,8 ...... </p>任务:创建两个名为ffr和ffs的函数,当给定n分别返回R(n)或S(n)时(注意R(1)= 1且S(1)= 2以避免逐个错误) 。不应假设n的最大值。 Sloane的<a href="http://oeis.org/A005228" title="链接:http://oeis.org/A005228">A005228</a>和<a href="http://oeis.org/A030124" title="链接:http://oeis.org/A030124">A030124</a> 。 <a href="http://mathworld.wolfram.com/HofstadterFigure-FigureSequence.html" title="链接:http://mathworld.wolfram.com/HofstadterFigure-FigureSequence.html">Wolfram MathWorld</a>维基百科: <a href="https://en.wikipedia.org/wiki/Hofstadter_sequence#Hofstadter_Figure-Figure_sequences" title="wp:Hofstadter_sequence#Hofstadter_Figure-Figure_sequences">Hofstadter图 - 图序列</a> 。 </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>ffr</code>是一个功能。
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testString: 'assert(typeof ffr === "function", "<code>ffr</code> is a function.");'
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- text: <code>ffs</code>是一个函数。
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testString: 'assert(typeof ffs === "function", "<code>ffs</code> is a function.");'
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- text: <code>ffr</code>应该返回整数。
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testString: 'assert(Number.isInteger(ffr(1)), "<code>ffr</code> should return integer.");'
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- text: <code>ffs</code>应该返回整数。
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testString: 'assert(Number.isInteger(ffs(1)), "<code>ffs</code> should return integer.");'
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- text: <code>ffr()</code>应该返回<code>69</code>
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testString: 'assert.equal(ffr(ffrParamRes[0][0]), ffrParamRes[0][1], "<code>ffr()</code> should return <code>69</code>");'
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- text: <code>ffr()</code>应返回<code>1509</code>
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testString: 'assert.equal(ffr(ffrParamRes[1][0]), ffrParamRes[1][1], "<code>ffr()</code> should return <code>1509</code>");'
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- text: <code>ffr()</code>应返回<code>5764</code>
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testString: 'assert.equal(ffr(ffrParamRes[2][0]), ffrParamRes[2][1], "<code>ffr()</code> should return <code>5764</code>");'
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- text: <code>ffr()</code>应返回<code>526334</code>
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testString: 'assert.equal(ffr(ffrParamRes[3][0]), ffrParamRes[3][1], "<code>ffr()</code> should return <code>526334</code>");'
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- text: <code>ffs()</code>应该返回<code>14</code>
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testString: 'assert.equal(ffs(ffsParamRes[0][0]), ffsParamRes[0][1], "<code>ffs()</code> should return <code>14</code>");'
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- text: <code>ffs()</code>应该返回<code>59</code>
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testString: 'assert.equal(ffs(ffsParamRes[1][0]), ffsParamRes[1][1], "<code>ffs()</code> should return <code>59</code>");'
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- text: <code>ffs()</code>应该返回<code>112</code>
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testString: 'assert.equal(ffs(ffsParamRes[2][0]), ffsParamRes[2][1], "<code>ffs()</code> should return <code>112</code>");'
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- text: <code>ffs()</code>应该返回<code>1041</code>
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testString: 'assert.equal(ffs(ffsParamRes[3][0]), ffsParamRes[3][1], "<code>ffs()</code> should return <code>1041</code>");'
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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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// noprotect
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function ffr(n) {
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return n;
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}
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function ffs(n) {
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return n;
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}
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```
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</div>
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### After Test
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<div id='js-teardown'>
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```js
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console.info('after the test');
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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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