5 use experimental 'multidimensional';
7 my @m = map { chomp; [ split // ] } <>;
12 for my $x (1 .. $xmax-2) {
13 for my $y (1 .. $ymax-2) {
17 for my $dx (0 .. $x-1) {
18 $visible = 0 if $m[$y][$dx] >= $h;
25 for my $dx ($x+1 .. $xmax-1) {
26 $visible = 0 if $m[$y][$dx] >= $h;
33 for my $dy (0 .. $y-1) {
34 $visible = 0 if $m[$dy][$x] >= $h;
41 for my $dy ($y+1 .. $ymax-1) {
42 $visible = 0 if $m[$dy][$x] >= $h;
50 say $count + 2* $xmax + 2*$ymax-4;