span class="binding-type">function</span> <span class="binding-type"><a href="https://github.com/janet-lang/spork/blob/285fced0323c318d26e6ecf767f2870aa948a3cf//spork/math.janet#L39">source</a></span> <pre class="binding-text">(quickselect arr k &amp;opt left right)

Rearrange items in `arr` so that all items in `[left, k]` range
are the smallest.
The `k`-th element will have the `(k - left + 1)`-th smallest value
in `[left, right]`.
Mutates `arr`.</pre><a href="https://janetdocs.org/math/quickselect">Commu