64 lines
2.3 KiB
Markdown
64 lines
2.3 KiB
Markdown
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---
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id: 5900f37a1000cf542c50fe8d
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challengeType: 5
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title: 'Problem 14: Longest Collatz sequence'
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videoUrl: ''
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localeTitle: 问题14：最长的Collatz序列
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---
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## Description
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<section id="description">为正整数集定义以下迭代序列： <div style="padding-left: 4em;"> <var>n</var> → <var>n</var> / 2（ <var>n</var>是偶数） </div><div style="padding-left: 4em;"> <var>n</var> →3 <var>n</var> + 1（ <var>n</var>为奇数） </div>使用上面的规则并从13开始，我们生成以下序列： <div style="text-align: center;"> 13→40→20→10→5→16→8→4→2→1 </div>可以看出，该序列（从13开始并在1结束）包含10个项。虽然尚未证实（Collatz问题），但是认为所有起始数字都在1处结束。在给定<code>limit</code>下，哪个起始数产生最长链？注意：一旦链条启动，条款允许超过一百万。 </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>longestCollatzSequence(14)</code>应该返回9。
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testString: 'assert.strictEqual(longestCollatzSequence(14), 9, "<code>longestCollatzSequence(14)</code> should return 9.");'
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- text: <code>longestCollatzSequence(5847)</code>应返回3711。
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testString: 'assert.strictEqual(longestCollatzSequence(5847), 3711, "<code>longestCollatzSequence(5847)</code> should return 3711.");'
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- text: <code>longestCollatzSequence(46500)</code>应返回35655。
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testString: 'assert.strictEqual(longestCollatzSequence(46500), 35655, "<code>longestCollatzSequence(46500)</code> should return 35655.");'
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- text: <code>longestCollatzSequence(54512)</code>应返回52527。
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testString: 'assert.strictEqual(longestCollatzSequence(54512), 52527, "<code>longestCollatzSequence(54512)</code> should return 52527.");'
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- text: <code>longestCollatzSequence(1000000)</code>应返回837799。
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testString: 'assert.strictEqual(longestCollatzSequence(1000000), 837799, "<code>longestCollatzSequence(1000000)</code> should return 837799.");'
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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 longestCollatzSequence(limit) {
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// Good luck!
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return true;
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}
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longestCollatzSequence(14);
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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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