26 lines
927 B
Markdown
26 lines
927 B
Markdown
## quickselect
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A tiny and fast [selection algorithm](https://en.wikipedia.org/wiki/Selection_algorithm) in JavaScript
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(specifically, [Floyd-Rivest selection](https://en.wikipedia.org/wiki/Floyd%E2%80%93Rivest_algorithm)).
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```js
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quickselect(array, k[, left, right, compareFn]);
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```
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Rearranges items so that all items in the `[left, k]` are the smallest.
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The `k`-th element will have the `(k - left + 1)`-th smallest value in `[left, right]`.
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- `array`: the array to partially sort (in place)
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- `k`: middle index for partial sorting (as defined above)
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- `left`: left index of the range to sort (`0` by default)
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- `right`: right index (last index of the array by default)
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- `compareFn`: compare function
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Example:
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```js
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var arr = [65, 28, 59, 33, 21, 56, 22, 95, 50, 12, 90, 53, 28, 77, 39];
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quickselect(arr, 8);
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// [39, 28, 28, 33, 21, 12, 22, 50, 53, 56, 59, 65, 90, 77, 95]
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// ^^ 8th item
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```
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