use File::Spec;
my  %cache;
foreach my $file (`find d:\\Teszt -type f`) {
    my $age = -M $file;
    my ($vol, $dir, $name) = File::Spec->splitpath($file);
    if (exists $cache{$vol, $dir}) {
        next if $age > $cache{$vol,$dir}[1];
    }
    $cache{$vol,$dir} = [$file, $age];
}
foreach my $newest_file_in_directory (map {$$_[0]} values %cache) {
    ... process file ...
}