4 use experimental 'multidimensional';
7 my @map = map { chomp; [ split // ] } <>;
8 my $xmax = $#{ $map[0] };
11 my @dx = (1, 0, -1, 0);
12 my @dy = (0, 1, 0, -1);
15 my @q = [ 1, 1, 1, [1, 1] ];
17 my ($x, $y, $steps, @path) = @{ shift @q };
19 next if $seen{$x,$y} && $seen{$x,$y} > $steps;
20 $seen{$x,$y} = $steps;
21 if ($x == $xmax-1 && $y == $ymax) {
22 say "at $x,$y, $steps, ", join(' ', map { "[$_->[0],$_->[1]]" } @path);
23 say "path len $steps";
27 $visited{$_->[0],$_->[1]} = 1 for @path;
29 my $nx = $x + $dx[$d];
30 my $ny = $y + $dy[$d];
31 next if $map[$ny][$nx] eq '#';
33 next if $visited{$nx,$ny};
34 next if $d != 0 && $map[$y][$x] eq '>';
35 next if $d != 1 && $map[$y][$x] eq 'v';
36 next if $d != 2 && $map[$y][$x] eq '<';
37 next if $d != 3 && $map[$y][$x] eq '^';
38 push @q, [ $nx, $ny, $steps+1, @path, [ $nx, $ny ] ];