63 lines
1.6 KiB
Markdown
63 lines
1.6 KiB
Markdown
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---
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title: Evaluate binomial coefficients
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id: 598de241872ef8353c58a7a2
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challengeType: 5
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videoUrl: ''
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localeTitle: 评估二项式系数
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---
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## Description
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<section id="description"><p>写一个函数来计算给定n和k值的二项式系数。 </p><p>推荐这个公式： </p> $ \ binom {n} {k} = \ frac {n！} {（nk）！k！} = \ frac {n（n-1）（n-2）\ ldots（n-k + 1）} { k（k-1）（k-2）\ ldots 1} $ </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>binom</code>是一个功能。
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testString: 'assert(typeof binom === "function", "<code>binom</code> is a function.");'
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- text: '<code>binom(5,3)</code>应该返回10。'
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testString: 'assert.equal(binom(5, 3), 10, "<code>binom(5,3)</code> should return 10.");'
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- text: '<code>binom(7,2)</code>应该返回21。'
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testString: 'assert.equal(binom(7, 2), 21, "<code>binom(7,2)</code> should return 21.");'
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- text: '<code>binom(10,4)</code>应该返回210。'
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testString: 'assert.equal(binom(10, 4), 210, "<code>binom(10,4)</code> should return 210.");'
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- text: '<code>binom(6,1)</code>应该返回6。'
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testString: 'assert.equal(binom(6, 1), 6, "<code>binom(6,1)</code> should return 6.");'
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- text: '<code>binom(12,8)</code>应该返回495。'
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testString: 'assert.equal(binom(12, 8), 495, "<code>binom(12,8)</code> should return 495.");'
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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 binom (n, k) {
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// Good luck!
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}
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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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