my %result = ();

foreach my $line (<DATA>) {
    chomp $line;
    my ($index, $value) = split(/ /, $line, 2);
    my $temp = \%result;
    foreach my $path (split (//, $index)) {
        $temp = $temp->{$path} ||= {}
    }
    $temp->{''} = [$index, $value];
}