[JOB] Perl Software Developer and Database programmer

[Peter Hickman]

Problem is that your code does not handle duplicate values in the alpha 
or beta lists. Compare

#!/usr/bin/perl -w

use strict;
use warnings;

my @alphas = qw/1 2 3 4 5 2/;
my @betas  = qw/1 2 3 1 2 3/;
my @results;

foreach my $alpha ( @alphas ) {
    foreach my $beta ( @betas ) {
        if ( $alpha == $beta ) {
            push @results, $beta;
        }
    }
}

print join ( ' ', @results ) . "\n";

Against

#!/usr/bin/perl -w

use strict;
use warnings;

my @alphas = qw/1 2 3 4 5 2/;
my @betas  = qw/1 2 3 1 2 3/;

my %beta;

@beta{@betas} = ();
my @results = grep {exists $beta{$_}} @alphas;

print join(',', @results), "\n";

The original produces 1 1 2 2 3 3 2 2, yours produces 1,2,3,2