https://icyveins7.github.io/tags/quickselect/Recent content in Quickselect on icyveins7's blogHugoen-usThis work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.Sun, 20 Jul 2025 20:00:00 +0800https://icyveins7.github.io/posts/2025/07/quickly-sketching-out-a-blockquickselect/Sun, 20 Jul 2025 20:00:00 +0800https://icyveins7.github.io/posts/2025/07/quickly-sketching-out-a-blockquickselect/<blockquote> <p>I wrote a blockwide quickselect. That&rsquo;s the post.</p> </blockquote> <p>As of today, NVIDIA&rsquo;s <code>cub</code> library has a few block-wide primitives to do sorting - like <code>BlockRadixSort</code> - but none that do the equivalent for the $k$&lsquo;th order statistic i.e the $k$-th smallest element.</p> <p>This would be functionally equivalent to the CPU&rsquo;s <code>std::nth_element</code>, but that <a href="https://en.cppreference.com/w/cpp/algorithm/nth_element.html">apparently uses Introselect</a>, which is a tad too much for me to want to implement. I&rsquo;m going to stick with the simpler <a href="https://en.m.wikipedia.org/wiki/Quickselect">quickselect</a>.</p>