getting to the perl

Let's represent the puzzle with this data structure:

for my $i ( 0..$#data ) 
{
    my $srow = int( $i / 9 );
    my $scol = $i % 9;
    my $sblk = int( $scol / 3 ) + int( $srow / 3 ) * 3;

    my $square = ( $data[$i] =~ m/^[1-9]$/ ) ? 
                 $data[$i] : undef;

    push @$_, \$square 
        for ( $row[$srow], $col[$scol], $block[$sblk] );
}