20 lines
490 B
Markdown
20 lines
490 B
Markdown
---
|
|
title: powerset
|
|
tags: math,algorithm,beginner
|
|
firstSeen: 2017-12-07T14:41:33+02:00
|
|
lastUpdated: 2020-12-28T13:49:24+02:00
|
|
---
|
|
|
|
Returns the powerset of a given array of numbers.
|
|
|
|
- Use `Array.prototype.reduce()` combined with `Array.prototype.map()` to iterate over elements and combine into an array containing all combinations.
|
|
|
|
```js
|
|
const powerset = arr =>
|
|
arr.reduce((a, v) => a.concat(a.map(r => [v].concat(r))), [[]]);
|
|
```
|
|
|
|
```js
|
|
powerset([1, 2]); // [[], [1], [2], [2, 1]]
|
|
```
|