Sorting algorithms/Heapsort: Difference between revisions

=={{header|Perl}}==

Translation of the pseudocode.

<lang perl>my @my_list = (2,3,6,23,13,5,7,3,4,5);

heap_sort(\@my_list);

print "@my_list\n";

exit;

sub heap_sort

{

my($list) = @_;

my $count = scalar @$list;

heapify($count,$list);

my $end = $count - 1;

while($end > 0)

{

@$list[0,$end] = @$list[$end,0];

sift_down(0,$end-1,$list);

$end--;

}

}

sub heapify

{

my ($count,$list) = @_;

my $start = ($count - 2) / 2;

while($start >= 0)

{

sift_down($start,$count-1,$list);

$start--;

}

}

sub sift_down

{

my($start,$end,$list) = @_;

my $root = $start;

while($root * 2 + 1 <= $end)

{

my $child = $root * 2 + 1;

$child++ if($child + 1 <= $end && $list->[$child] < $list->[$child+1]);

if($list->[$root] < $list->[$child])

{

@$list[$root,$child] = @$list[$child,$root];

$root = $child;

}else{ return }

}

}</lang>