62 lines
1.8 KiB
Markdown
62 lines
1.8 KiB
Markdown
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---
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id: 5900f3a11000cf542c50feb4
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challengeType: 5
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title: 'Problem 53: Combinatoric selections'
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videoUrl: ''
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localeTitle: 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, "<code>combinatoricSelections(1000)</code> should return 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, "<code>combinatoricSelections(10000)</code> should return 4431.");'
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- text: <code>combinatoricSelections(100000)</code>应返回4255。
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testString: 'assert.strictEqual(combinatoricSelections(100000), 4255, "<code>combinatoricSelections(100000)</code> should return 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, "<code>combinatoricSelections(1000000)</code> should return 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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