- say $sum;
- $rounds[$round] = $sum;
- say "round $round sum $sum";
- my $map = join("\n", map { join('', @$_) } @map);
- if ($seen{$map}) {
- say "round $round seen also at $seen{$map}";
- my $period = $round - $seen{$map};
- my $total = 1000000000;
- $total -= $round;
- $total %= $period;
- say "looking at ", $round - $period + $total;
- say $rounds[$round-$period+$total];
- last;
- }
- $seen{$map} = $round;