freeCodeCamp/curriculum/challenges/chinese/10-coding-interview-prep/project-euler/problem-3-largest-prime-factor.md

---
id: 5900f36f1000cf542c50fe82
challengeType: 5
videoUrl: ''
title: 问题3：最大素数
---

## Description
<section id="description">
13195的主要因子是5、7、13和29。
给定<code>数字</ code>的最大素数是多少？
</section>

## Instructions
<section id="instructions">
</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>largestPrimeFactor(2)</code>应该返回2。
    testString: assert.strictEqual(largestPrimeFactor(2), 2);
  - text: <code>largestPrimeFactor(3)</code>应该返回3。
    testString: assert.strictEqual(largestPrimeFactor(3), 3);
  - text: <code>largestPrimeFactor(5)</code>应该返回5。
    testString: assert.strictEqual(largestPrimeFactor(5), 5);
  - text: <code>largestPrimeFactor(7)</code>应该返回7。
    testString: assert.strictEqual(largestPrimeFactor(7), 7);
  - text: <code>largestPrimeFactor(13195)</code>应该返回29。
    testString: assert.strictEqual(largestPrimeFactor(13195), 29);
  - text: <code>largestPrimeFactor(600851475143)</code>应该返回6857。
    testString: assert.strictEqual(largestPrimeFactor(600851475143), 6857);

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='js-seed'>

```js
function largestPrimeFactor(number) {
  // Good luck!
  return true;
}

largestPrimeFactor(13195);

```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```

/section>