my %elements = map { $_ => 1 } @array;

foreach my $element (@array) {
    # now construct copies of each $element 
    # based on the patterns you describe
    my $transformed_element = transform($element);
    # then let the hash find the transformation
    print "Success!" if exists $elements{$transformed_element};
}

##</code><code>##

my %elements = map { $_ => 1 } @array;

foreach my $element (@array) {
    foreach my $tranformation (keys %transformations) {
        my $transformed_element = $transformations{$tranformation}->($element);
        if (exists $elements{$transformed_element}) {
            print "Found a $tranformation of $element";
        }
    }
}