#!/usr/bin/perl

use strict;
use warnings;
use Benchmark qw(:all) ;

my $n = 100000;
our %hash1;
@hash1{1..$n} = 1 x $n;
my $n2 = 100000;
our %hash2;
@hash2{1..$n2} = 1 x $n2;
my $n3 = 1000000;
our %hash3;
@hash3{1..$n3} = 1 x $n3;

cmpthese( 1000, {
    'Method 1' => sub  {
			my @k = keys %hash1;
			my $v = scalar @k;
		}, 
    '100K' => sub {
		   my $v = scalar keys %hash2;
		},
   '1 Mill' => sub {
		   my $v = scalar keys %hash3;
		}
	}
    );