#! perl -slw
use strict;
use Benchmark qw[ cmpthese ];

our $SIZE ||= 1000;
our $ITERS||= -5;

sub spliceIt{
    my @a = reverse 0 .. $SIZE;
    unshift @a, splice @a, $SIZE, 1; ## Update: changed push to unshift!
#   print "@a";
}

sub heapIt {
    my @a = reverse 0 .. $SIZE;
    $a[ $SIZE ] = $SIZE + 1;
    moveUp( \@a, $SIZE );
#   print "@a";
}

sub moveUp {
    my( $ref, $l ) = @_;
    my $p = int $l /2;
    return if $p >= $l;
    @{ $ref }[ $p, $l ] = @{ $ref }[ $l, $p ];
    moveUp( $ref, $p );
}

print "Testing $SIZE items for $ITERS iterations";

cmpthese( $ITERS, {
    splice => \&spliceIt,
    heap   => \&heapIt,
});
__END__
P:\test>heaptest -ITERS=-5 -SIZE=100
Testing 100 items for -5 iterations
          Rate   heap splice
heap   19502/s     --   -37%
splice 30887/s    58%     --

P:\test>heaptest -ITERS=-5 -SIZE=1000
Testing 1000 items for -5 iterations
         Rate   heap splice
heap   3159/s     --    -4%
splice 3288/s     4%     --

P:\test>heaptest -ITERS=-5 -SIZE=10000
Testing 10000 items for -5 iterations
        Rate   heap splice
heap   327/s     --    -0%
splice 328/s     0%     --

P:\test>heaptest -ITERS=-5 -SIZE=20000
Testing 20000 items for -5 iterations
        Rate splice   heap
splice 159/s     --    -1%
heap   160/s     1%     --