22 lines
532 B
Markdown
22 lines
532 B
Markdown
---
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title: Powerset
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tags: math,algorithm
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expertise: beginner
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cover: blog_images/new-plant.jpg
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firstSeen: 2017-12-07T14:41:33+02:00
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lastUpdated: 2021-09-27T15:27:07+02:00
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---
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Returns the powerset of a given array of numbers.
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- Use `Array.prototype.reduce()` combined with `Array.prototype.map()` to iterate over elements and combine into an array containing all combinations.
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```js
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const powerset = arr =>
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arr.reduce((a, v) => a.concat(a.map(r => r.concat(v))), [[]]);
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```
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```js
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powerset([1, 2]); // [[], [1], [2], [1, 2]]
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```
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