#!/usr/bin/perl
use 5.016;
use warnings;
use List::Util qw(reduce);

sub f {
	my $r = reduce {
		defined $a->[2] or return $a;
		my $d = ($a->[2] <=> $b);
		($a->[1] == $d or $d == 0 or $a->[1] == 0) ?
			[$a->[0] + 1, $a->[1] || $d, $b] : [$a->[0], $a->[1], undef];
	} [0, 0, $_[0]], @_;

	return ($r->[0] == @_ ? ["AS", "EQ", "DES"]->[$r->[1] + 1] : $r->[0]);
}

say f(6,6,3,2,6,4,7,4,7,4);
say f(2,3,4,4,4,6,6,6,7,7);
say f(7,7,6,6,6,4,4,4,3,2);
say f(1,1,1,1,1,1,1,1,1,1);
say f();
say f(1);

sub g {
	(@_ < 1) and return [];
	return reduce {
		$a->[-1]->[-1] <= $b ?
			[ @{$a}[0 .. $#{$a} - 1], [@{$a->[-1]}, $b]] :
			[ @{$a}, [$b] ]
	} [[$_[0]]], @_[1 .. $#_];
}

use Data::Dumper;
local $Data::Dumper::Terse = 1;
local $Data::Dumper::Indent = 0;

say Dumper(g(8,3,4,9,9,10,6,1,4,3));
say Dumper(g(1,3,3,4,4,6,8,9,9,10));
say Dumper(g(10,9,9,8,6,4,4,3,3,1));
say Dumper(g(1,1,1,1,1,1,1,1,1,1));
say Dumper(g());
say Dumper(g(1));