my @list1 = qw(0 1 3);
my @list2 = qw(2 4 6 5);

my @sortedBiglist = sort { $a <=> $b } (@list1, @list2);
my @predefList = (0..$#sortedBiglist);
if ("@sortedBiglist" eq "@predefList"){
  print "all ok\n";
}