sub hashGen {
    my $idx = 0;
    my %mArray;
    ++$mArray{ $nums[ ++$idx ] } while keys %mArray < $uSize;
    return keys %mArray;
}

__END__
C:\test>junk
             Rate   grepGen    mapGen  firstGen  smartGen   hashGen shuffleEm
grepGen    45.2/s        --      -54%      -79%      -96%      -99%     -100%
mapGen     97.9/s      116%        --      -54%      -91%      -98%     -100%
firstGen    214/s      374%      119%        --      -80%      -97%      -99%
smartGen   1074/s     2274%      997%      401%        --      -83%      -96%
hashGen    6500/s    14275%     6540%     2932%      506%        --      -75%
shuffleEm 25619/s    56551%    26068%    11849%     2286%      294%        --