use strict; use warnings; use Time::HiRes qw( time ); my $start_run = time(); for my $n (100..1_00_000_000) { my $r = reverse($n); my $x = 100; while ($x <= $n) { if (int($n / $x) * ($n % $x) == $r) { print "$n\n"; last; } $x *= 10; } } my $end_run = time(); my $run_time = $end_run - $start_run; print "Time taken: ".$run_time." sec\n";