Without knowing the exact question posed, you did not need to push stuff onto @array3. All you had to do was this for that: my @array3 = sort(@array1);

As for generating the sub-arrays, give me a few minutes and I'll have something different than using indexes.

Update: working code.

#!/usr/bin/perl

use warnings;
use strict;

use Data::Dumper;
$Data::Dumper::Indent = 1;

my @array1 = (1,2,3,4,5,6,7,8,3,5,6,3,8,1,7,8);
my @array3 = sort(@array1);

my @subarrays = ( [] );
my $last = 0;
for ( @array1 ) {
    push(@subarrays, []) if $_ < $last;
    push(@{$subarrays[-1]},$_);
    $last = $_;
}

print Dumper(\@array1);
print Dumper(\@subarrays);
print Dumper(\@array3);

exit;

__END__
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