aoc2015

commit 9627aa19c21ef74417fb11b8e83daa084c18710f
parent 80baa846db2f86143cd57ed47d67deb0992e1a98
Author: Samir Parikh <noreply@samirparikh.com>
Date:   Thu, 10 Nov 2022 20:40:31 +0000

work in progress

Diffstat:
M
day18/Day18.pm
 | 
62
+++++++++++++++++++++++++++++++++++++++++++++++++-------------
M
day18/day18.pl
 | 
20
+++++++-------------

2 files changed, 56 insertions(+), 26 deletions(-)
diff --git a/day18/Day18.pm b/day18/Day18.pm
@@ -5,7 +5,18 @@ use warnings;
 use v5.32;
 use Exporter qw( import );
 
-our @EXPORT = qw( init_lights update_lights );
+our @EXPORT = qw( init_lights flash_lights display_lights );
+
+sub setup_neighbors
+{
+    my @neighbors;
+    foreach my $nr (-1 .. 1) {
+        foreach my $nc (-1 .. 1) {
+            push @neighbors => [$nr, $nc] unless ($nr == 0 && $nc == 0);
+        }
+    }
+    return \@neighbors;
+}
 
 sub init_lights
 {
@@ -24,27 +35,52 @@ sub init_lights
 
     # Add an extra row at the end to serve as a boundary when we do the neighbor
     # comparisons later on.
-    push @lights => [ '.' x scalar @{ $lights[0] } ];
+    push @lights => [ ('.') x scalar @{ $lights[0] } ];
     return \@lights;
 }
 
-sub setup_neighbors
+sub update_light
 {
-    my @neighbors;
-    foreach my $nr (-1 .. 1) {
-        foreach my $nc (-1 .. 1) {
-            push @neighbors => [$nr, $nc] unless ($nr == 0 && $nc == 0);
+    my $row    = shift;
+    my $col    = shift;
+    my @lights = @{ shift() };
+    my @neighbors = @{ setup_neighbors() };
+    my $neighbors_on = 0;
+    foreach my $neighbor ( @neighbors ) {
+        my $neighbor_row = $row + $neighbor->[0];
+        my $neighbor_col = $col + $neighbor->[1];
+        say "------------";
+        say "row $row + neighbor_row $neighbor->[0] = $neighbor_row";
+        say "col $col + neighbor_col $neighbor->[1] = $neighbor_col";
+        say "light is <$lights[ $neighbor_row ][ $neighbor_col ]>";
+        $neighbors_on++ if ( $lights[ $neighbor_row ][ $neighbor_col ] eq '#' );
+    }
+    say "light $row, $col has $neighbors_on neighbors that are on";
+    if ( $lights[ $row ][ $col ] eq '#' ) {
+        return ( $neighbors_on == 2 || $neighbors_on == 3 ) ? '#' : '.';
+    } else {
+        return ( $neighbors_on == 3 ) ? '#' : '.';
+    }
+}
+
+sub flash_lights
+{
+    my $current_state = shift;
+    my @next_state = @{ $current_state };
+    my $rows   = scalar @{ $current_state };
+    my $columns = scalar @{ $current_state->[ 0 ] };
+    foreach my $row ( 0 .. $rows - 2 ) {
+        foreach my $col ( 0 .. $columns - 2 ) {
+            $next_state[ $row ][ $col ] = update_light( $row, $col, $current_state );
         }
     }
-    return \@neighbors;
+
+    return \@next_state;
 }
 
-sub update_lights
+sub display_lights
 {
-    my @lights = @{ shift() };
-    my $rows   = scalar @lights;
-    my $columns = scalar @{ $lights[ 0 ] };
-    my @neighbors = @{ setup_neighbors() };
+    say "@{ $_ }" foreach ( @{ shift() } );
 }
 
 1;
diff --git a/day18/day18.pl b/day18/day18.pl
@@ -10,23 +10,17 @@ use List::Util qw( max );
 
 @ARGV = "input" unless @ARGV;
 chomp( my $input = do { local $/; <> } );
-
-# initialize variables to declare number of steps, arrays to hold current state
-# of lights, the next state, and index offsets for the neighbors, s well as
-# variables to hold number of rows and columns.
-my $STEPS         = 4;
+my $STEPS         = 1;
 my $state         = init_lights( $input );
-#my @current_state = @{ init_lights( $input ) };
-#my @next_state;
-#my $rows          = scalar @current_state;
-#my $columns       = scalar @{ $current_state[ 0 ] };
-#my @neighbors     = @{ setup_neighbors() };
+
+say "Initial state:";
+display_lights( $state );
 
 foreach ( 1 .. $STEPS )
 {
-#    foreach my $row ( 0 .. $rows - 2 ) {
-#        foreach my $column ( 0 .. $columns - 2 ) {
-    $state = update_lights( $state );
+    $state = flash_lights( $state );
+    say "After step $_:";
+    display_lights( $state );
 }
 say "part 1: ";
 say "part 2: ";