#! 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%     --

##</code><code>##

 a) 0 [ 16 ] b) 0 [ 16 ] c) 0 [ 16 ] d) 0 [ 16 ] e) 0 * 17 ]
    1 [ 12 ]    1 [ 12 ]    1 [ 12 ]    1 * 17 ]    1 * 16 ]
    2 [ 13 ]    2 [ 13 ]    2 [ 13 ]    2 [ 13 ]    2 [ 13 ]
    3 [ 10 ]    3 [ 10 ]    3 * 17 ]    3 * 12 ]    3 [ 12 ]
    4 [  9 ]    4 [  9 ]    4 [  9 ]    4 [  9 ]    4 [  9 ]
    5 [ 11 ]    5 [ 11 ]    5 [ 11 ]    5 [ 11 ]    5 [ 11 ]
    6 [  7 ]    6 * 17 ]    6 * 10 ]    6 [ 10 ]    6 [ 10 ]
    7 [  6 ]    7 [  6 ]    7 [  6 ]    7 [  6 ]    7 [  6 ]
    8 [  5 ]    8 [  5 ]    8 [  5 ]    8 [  5 ]    8 [  5 ]
    9 [  4 ]    9 [  4 ]    9 [  4 ]    9 [  4 ]    9 [  4 ]
   10 [  3 ]   10 [  3 ]   10 [  3 ]   10 [  3 ]   10 [  3 ]
   11 [  8 ]   11 [  8 ]   11 [  8 ]   11 [  8 ]   11 [  8 ]
   12 * 17 ]   12 *  7 ]   12 [  7 ]   12 [  7 ]   12 [  7 ]