freeCodeCamp/curriculum/challenges/chinese/10-coding-interview-prep/project-euler/problem-24-lexicographic-permutations.md

---
id: 5900f3841000cf542c50fe97
challengeType: 5
videoUrl: ''
title: 问题24：字典排列
---

## Description
<section id="description">置换是对象的有序排列。例如，3124是数字1,2,3和4的一种可能的排列。如果所有排列都以数字或字母顺序列出，我们称之为词典顺序。字典排列0,1和2是： <div style="text-align: center;"> 012 021 102 120 201 210 </div>数字0,1,2,3,4,5,6,7,8和9的第<var>n</var>个词典排列是什么？ </section>

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

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>lexicographicPermutations(699999)</code>应该返回1938246570。
    testString: assert(lexicographicPermutations(699999) == 1938246570);
  - text: <code>lexicographicPermutations(899999)</code>应该返回2536987410。
    testString: assert(lexicographicPermutations(899999) == 2536987410);
  - text: <code>lexicographicPermutations(900000)</code>应该返回2537014689。
    testString: assert(lexicographicPermutations(900000) == 2537014689);
  - text: <code>lexicographicPermutations(999999)</code>应该返回2783915460。
    testString: assert(lexicographicPermutations(999999) == 2783915460);

```

</section>

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

<div id='js-seed'>

```js
function lexicographicPermutations(n) {
  // Good luck!
  return n;
}

lexicographicPermutations(999999);

```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```

/section>