use strict;
use warnings;


problem([1,2,3]);

sub problem {
	print2DArray(@_);  #Output: 1 2 3
	reverseArray1(@_);
	print2DArray(@_);  #Output: 1 2 3
	reverseArray2(@_);
	print2DArray(@_);  #Output: 3 2 1
}

sub reverseArray1 {
	my @arr = @_;
	for my $i (0 .. $#arr) {
		$arr[$i] = [reverse @{$arr[$i]}];
	}
}

sub reverseArray2 {
	my @arr = @_;
	for my $i (0 .. $#arr) {
		@{$arr[$i]} = reverse @{$arr[$i]};
	}
}

sub print2DArray {
	for my $i (0 .. $#_) {  # How does that work for the nested for loop?
		for(my $j=0;$j<scalar(@{$_[$i]});$j++){  # $#_[$i] doesn't work
			print $_[$i][$j]," ";
		}
		print "\n";
	}
}