#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

print Dumper P(\@ARGV);

sub P {
   my($m,$e,$p)=(@_,[],[]);
   !@{$m}and push@{$p},$e or
   P(@_=@{$m}and pop and[@_],[@{$e}],$p)and
   P(@_=@{$m}and pop and[@_],[sort@{$e},$m->[-1]],$p);
   [sort{@{$a}<=>@{$b}}@{$p}]
}