Less well-known, not only is the selection of the pivot element important, but also the selection of which side you use recursion: "[...] it always recurses on

Less well-known, not only is the selection of the pivot element important, but also the selection of which side you use recursion: "[...] it always recurses on the first sub-partition, and iterates on the second sub-partition; but instead, it should always recurse on the smaller sub-partition, and iterate on the larger sub-partition [...] our attack constructs an input array of N elements that causes qsort() to recurse N/4 times." https://www.qualys.com/2017/06/19/stack-clash/stack-clash.txt https://www.qualys.com/2017/06/19/stack-clash/stack-clash.tx... That's from last month.