# see for the actual problem to solve: https://adventofcode.com/2022/day/8
use strict;
use warnings;
use PDL;
use PDL::NiceSlice;

my $debug = 1;
my $x = rcols( *DATA, {COLSEP => qr//}, []);

is_visible( $x );
# piddle rotated 90° counterclockwise
is_visible( $x->transpose()->slice( ':', '-1:0' ) );


sub is_visible{
	my $pdl = shift;
	print "Working on the piddle: $pdl(skipping first and last rows)\n" if $debug;
	#
	# the idea is to consider only rows from second one to last but one
	foreach my $nrow ( 1 ..  nelem($pdl->slice('0,'))-2 ){
		#
		# now the idea is to consider only from second element to last but one
		print "in ROW $nrow considering only: ", $pdl->slice("1:-2,($nrow)"),"\n" if $debug;
		#
		# ..and now checking these elements..
		foreach my $to_check ( $pdl->slice("1:-2,($nrow)")->dog ){
			print "\tchecking $to_check\n" if $debug;
			#
			# ...against all other members of the rows
			# like in (PSEUDOCODE) assuming @array being the current row
			# foreach my $idx_to_check ( 1 .. $#array-1 ){
			#     my $res = map{ my_check( $array[$idx_to_check], $array[$_]) }grep{ $idx_to_check != $_ } 0..$#array;
			# }
		}
	}
}

__DATA__
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