use strict;
use warnings;
use List::MoreUtils;
use Benchmark qw(cmpthese);

my @values = map {int rand 10} 1 .. 1000;

for my $sub (\&UtilsM, \&UtilsH, \&Grep, \&Map, \&For,) {
    print join ("\t", sort $sub->(@values)), "\n";
}

cmpthese (-1, {
        UtilsM => sub {UtilsM (@values)},
        UtilsH => sub {UtilsH (@values)},
        Grep  => sub {Grep (@values)},
        Map   => sub {Map (@values)},
        For   => sub {For (@values)},
    }
);


sub UtilsM {
    return List::MoreUtils::uniq (@_);
}

sub UtilsH {
    my %h;
    return map { $h{$_}++ == 0 ? $_ : () } @_;
}

sub Grep {
    my %unique =();

    grep {$unique{$_} = undef} @_;
    return keys %unique;
}

sub Map {
    my %unique =();

    map {$unique{$_} = undef} @_;
    return keys %unique;
}

sub For {
    my %unique =();

    $unique{$_} = undef for @_;
    return keys %unique;
}