@b = sort {$a <=> $b} @b; @a = sort {$a <=> $b} @a; print "@b\n"; for (@a) { if (defined($b[$i])) { if (not $_ == $b[$i]) { push @c, $_ } else { $i++ } } else { push @c, @a[($j..$#a)]; last; } $j++; }