62 lines
1.5 KiB
Markdown
62 lines
1.5 KiB
Markdown
---
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id: 5900f3a11000cf542c50feb4
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challengeType: 5
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videoUrl: ''
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title: 问题53：组合选择
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---
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## Description
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<section id="description">有十种方法从五种中选择三种，12345：123,124,125,134,135,145,234,235,245和345在组合学中，我们使用符号，5C3 = 10.一般来说， <p> nCr = n！r！（n-r）！ ，其中r≤n，n！ = n×（n-1）×...×3×2×1和0！ = 1。 </p><p>直到n = 23，一个值超过一百万：23C10 = 1144066.对于1≤n≤100，nCr的多少，不一定是不同的值大于一百万？ </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>combinatoricSelections(1000)</code>应返回4626。
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testString: assert.strictEqual(combinatoricSelections(1000), 4626);
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- text: <code>combinatoricSelections(10000)</code>应该返回4431。
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testString: assert.strictEqual(combinatoricSelections(10000), 4431);
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- text: <code>combinatoricSelections(100000)</code>应返回4255。
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testString: assert.strictEqual(combinatoricSelections(100000), 4255);
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- text: <code>combinatoricSelections(1000000)</code>应该返回4075。
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testString: assert.strictEqual(combinatoricSelections(1000000), 4075);
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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 combinatoricSelections(limit) {
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// Good luck!
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return 1;
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}
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combinatoricSelections(1000000);
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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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