I just came across an interesing mathematical widget. 

111,111,111 * 111,111,111 = 12,345,678,987,654,321

So here is the challenge:

1 Write a subroutine that takes one argument. This argument is to be a positive integer.

2 The sub is to find all the symmetrical squares between zero and the supplied argument.

3 Not only must the square be symmetrical, the number itself must also be symmetrical - thus conforming to the original example where both the number and its square exhibit symetry.

4 The sub is to return a reference to a hash which contains only those symetrical numbers that have symmetrical squares as its keys with the matching symmetrical squares as the values.

5 There is no requirement for use strict.

Here is a very straight forward example with the test code and desired output included. 

use strict;

my $ref = symetrical(100);
for my $key (sort {$a <=> $b} keys %$ref) {
   printf "%-10d%d\n",$key,$ref->{$key};
}

sub symetrical {
    my %symet;
    my $max = shift;
    for my $i (0..$max) {
        my $square = $i * $i;
        if (sym($square)) {
            $symet{$i} = $square if sym($i);
        }            
    }
    sub sym {
       $num = shift;
       ($num eq reverse $num) ? $num : '';
    }
    return \%symet;
}


__END__

Sample output

1         1
2         4
3         9
11        121
22        484
101       10201
111       12321
121       14641
202       40804
212       44944

[download]
Official scoring will be done with the "Official GOLF score" (tm) code presented below. It comfoms to the standard set down in RFC foobar with the baz ammendments. In short this standard specifies that we count the chars from (but not including) the subs opening curly up to (but not including) the closing curly. Leading/trailing whitespace and newlines are not counted. The code for this is presented below. 
package GOLF;

use strict;

my $code = <<'CODE';
 
# paste code in here

CODE

$code =~ s/^\s+|\s+$//gm;
$code =~ s/\n//g;
$code =~ s/}$//;
$code =~ s/^sub\s+(\w+)\s*{//;

printf "Length of sub '$1' => %d chars\n", length $code;

[download]

My effort stands at 194 chars, but I think I can do better ;-)

cheers

tachyon

s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

In reply to Symmetrical Numbers (GOLF) by tachyon

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