No comments on Heap not having ever used it.
However, unless you are dynamically adding and removing items to your dataset wouldn't something like:
sub smallest_n (&\@$) {
my ($cmp, $arrayref, $n) = @_;
return unless $n && @$arrayref;
$n = @$arrayref if @$arrayref < $n;
my @results = sort $cmp @$arrayref[0..$n-1];
local ($a, $b);
$a = pop @results;
for (my $i = $n; $i < @$arrayref; $i++) {
$b = $arrayref->[$i];
if ($cmp->() == 1) {
@results = sort $cmp (@results, $b);
$a = pop @results;
};
};
return (@results, $a);
};
use Test::More tests => 1;
use List::Util qw(shuffle);
my @a = shuffle (1..100000);
my @b = smallest_n {$a <=> $b} @a, 5;
is_deeply [@b], [1,2,3,4,5];
be easier? The support for the heap datastructure will add a fair bit of overhead with your large dataset, so I wouldn't use one unless you need it.
Update: totally misready what blakem was proposing. D'oh.
-
Are you posting in the right place? Check out Where do I post X? to know for sure.
-
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big>
<blockquote> <br /> <dd>
<dl> <dt> <em> <font>
<h1> <h2> <h3> <h4>
<h5> <h6> <hr /> <i>
<li> <nbsp> <ol> <p>
<small> <strike> <strong>
<sub> <sup> <table>
<td> <th> <tr> <tt>
<u> <ul>
-
Snippets of code should be wrapped in
<code> tags not
<pre> tags. In fact, <pre>
tags should generally be avoided. If they must
be used, extreme care should be
taken to ensure that their contents do not
have long lines (<70 chars), in order to prevent
horizontal scrolling (and possible janitor
intervention).
-
Want more info? How to link
or How to display code and escape characters
are good places to start.