With just a few syntax changes (no change to the logic) I can shave off about 8% of the run time...

sub sortQ2
{
    my ($s, $e, $dst) = @_;
    my $m = $s - 1;
    
    ($dst->[$_] < $dst->[$e]) && (
        ++$m,
        ($dst->[$m], $dst->[$_]) = ($dst->[$_], $dst->[$m]),
    ) for ($s .. $e-1);
    
    ++$m;
    
    ($dst->[$m], $dst->[$e]) = ($dst->[$e], $dst->[$m]);
    
    sortQ2($s, $m-1, $dst) if ($s < $m - 1);
    sortQ2($m+1, $e, $dst) if ($m + 1 < $e);
}

[download]

How does this speed things up? Each pair of { ... } introduces a lexical scope; scopes have a small runtime overhead. I've removed all of them except for the one surrounding the entire function.

You can get a few percent extra using Data::Alias which allows you to avoid some arrayref dereferencing operations:

use Data::Alias;

sub sortQ2
{
    my ($s, $e, $dst) = @_;
    alias my @dst = @$dst;
    my $m = $s - 1;
    
    ($dst[$_] < $dst[$e]) && (
        ++$m,
        ($dst[$m], $dst[$_]) = ($dst[$_], $dst[$m]),
    ) for ($s .. $e-1);
    
    ++$m;
    
    ($dst[$m], $dst[$e]) = ($dst[$e], $dst[$m]);
    
    ($s < $m - 1) && sortQ2($s, $m-1, $dst);
    ($m + 1 < $e) && sortQ2($m+1, $e, $dst);
}

[download]

Overall, this is about 12% faster than the original.

use Moops; class Cow :rw { has name => (default => 'Ermintrude') }; say Cow->new->name

In reply to Re: quick sort. How do it faster by tobyink
in thread quick sort. How do it faster by builat

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.