05.raku

use v6d;

my @input = 'input'.IO.lines;

my %grid;
my $overlap = 0;
my @diag;

for @input {
    my ($x1, $y1, $x2, $y2) = .split(/\D+/, :skip-empty);

    if ($x1 == $x2) {
        ($y1, $y2) = ($y2, $y1)  if $y1 > $y2;
        for $y1..$y2 -> $y {
            $overlap++  if ++%grid{$x1}{$y} == 2;
        }
    } elsif ($y1 == $y2) {
        ($x1, $x2) = ($x2, $x1)  if $x1 > $x2;
        for $x1..$x2 -> $x {
            $overlap++  if ++%grid{$x}{$y1} == 2;
        }
    } else {
        @diag.push([$x1, $y1, $x2, $y2]);
    }
}
say "Part One: $overlap";

for (@diag) {
    my ($x1, $y1, $x2, $y2) = .List;
    if ($x1 > $x2) { 
        ($x1, $x2) = ($x2, $x1);
        ($y1, $y2) = ($y2, $y1);
    }
    my $y_incr = ($y1 > $y2) ?? -1 !! 1;
    for ($x1 .. $x2) {
        $overlap++  if ++%grid{$_}{$y1} == 2;
        $y1 += $y_incr;
    }
}
print "Part Two: $overlap\n";