aoc2022

commit 580df9e0a97f533bf1d6a8e949b80046f260b7f3
parent 25e9640fd228365b33db3e9bc126cf8287f20acd
Author: Samir Parikh <noreply@samirparikh.com>
Date:   Tue, 27 Dec 2022 22:49:00 +0000

solve part 2 of day08

Diffstat:
M
day08/day08.pl
 | 
63
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---

1 file changed, 60 insertions(+), 3 deletions(-)
diff --git a/day08/day08.pl b/day08/day08.pl
@@ -16,7 +16,8 @@ foreach ( split /\n/, $input ) {
 
 my $rows = scalar @trees;
 my $columns = scalar @{ $trees[0] };
-my $part1 = ( 2 * $columns ) + 2 * ( $rows - 2 );
+my $visible = ( 2 * $columns ) + 2 * ( $rows - 2 );
+my @scenic_scores;
 
 my %check = (
     up      => sub {
@@ -44,15 +45,71 @@ my %check = (
     },
 );
 
+my %view_distance = (
+    up      => sub {
+        my ( $x, $y ) = @_;
+        my $distance = 0;
+        foreach my $yn ( reverse 0 .. $y - 1 ) {
+            $distance++;
+            if ( $trees[ $y ][ $x ] <= $trees[ $yn ][ $x ] ) {
+                last;
+            }
+        }
+        return $distance;
+    },
+
+    down    => sub {
+        my ( $x, $y ) = @_;
+        my $distance = 0;
+        foreach my $yn ( $y + 1 .. $rows - 1 ) {
+            $distance++;
+            if ( $trees[ $y ][ $x ] <= $trees[ $yn ][ $x ] ) {
+                last;
+            }
+        }
+        return $distance;
+    },
+
+    left    => sub {
+        my ( $x, $y ) = @_;
+        my $distance = 0;
+        foreach my $xn ( reverse 0 .. $x - 1 ) {
+            $distance++;
+            if ( $trees[ $y ][ $x ] <= $trees[ $y ][ $xn ] ) {
+                last;
+            }
+        }
+        return $distance;
+    },
+
+    right   => sub {
+        my ( $x, $y ) = @_;
+        my $distance = 0;
+        foreach my $xn ( $x + 1 .. $columns - 1 ) {
+            $distance++;
+            if ( $trees[ $y ][ $x ] <= $trees[ $y ][ $xn ] ) {
+                last;
+            }
+        }
+        return $distance;
+    },
+);
+
 for my $y ( 1 .. $rows - 2 ) {
     for my $x ( 1 .. $columns - 2 ) {
         foreach my $direction ( qw( up down left right ) ) {
             if ( $check{ $direction }->( $x, $y ) ) {
-                $part1++;
+                $visible++;
                 last;
             }
         }
+        my $scenic_score = 1;
+        foreach my $direction ( qw( up down left right ) ) {
+            $scenic_score *= $view_distance{ $direction }->( $x, $y );
+        }
+        push @scenic_scores => $scenic_score;
     }
 }
 
-say "part 1: ", $part1;
+say "part 1: ", $visible;
+say "part 2: ", max @scenic_scores;