2020, tracking

1 files changed, 40 insertions, 0 deletions

diff --git a/2020/day3/toboggans.pl b/2020/day3/toboggans.pl
new file mode 100644
index 0000000..ebf7ae4
--- /dev/null
+++ b/2020/day3/toboggans.pl
@@ -0,0 +1,40 @@
+use strict;
+use warnings;
+# use Smart::Comments;
+use DDP;
+
+open my $fh, '<', "input" or die "no input present, $!";
+chomp(my @forest = <$fh>);
+close $fh;
+my $len = scalar @forest;
+
+my @right_ms = qw/1 3 5 7 1/;
+my @down_ms = qw/ 1 1 1 1 2/;
+my $runs = $#right_ms;
+
+my $all_trees = 1;
+
+foreach my $run (0..$runs) {
+
+    my $toboggan = 0;
+    my $trees = 0;
+    my $down_mov = $down_ms[$run];
+    my $right_mov = $right_ms[$run];
+
+    for (my $line = 0; $line < $len; $line += $down_mov) {
+        my $curr = substr($forest[$line], $toboggan, 1);
+        if ($curr eq "#") {
+            $trees++;
+        }
+        $toboggan = ($toboggan + $right_mov) % 31;
+    }
+    $trees ||= 1;
+    $all_trees *= $trees;
+    ### this run is
+    ### $right_mov
+    ### $down_mov
+    ### got: $trees
+    ### so far: $all_trees
+}
+
+print("$all_trees");