aoc2021

commit 6ab15f4b31aa97d85cee5e75aa8a52a311f7c1c2
parent aea1e9ebf5d71e3f25a82fcea9fc4f4447191d63
Author: Samir Parikh <noreply@samirparikh.com>
Date:   Thu,  9 Dec 2021 00:30:28 +0000

update to get proper solution to Day 05 Part 2

Diffstat:
M
day05-2.pl
 | 
22
+++++++++-------------

1 file changed, 9 insertions(+), 13 deletions(-)
diff --git a/day05-2.pl b/day05-2.pl
@@ -4,21 +4,14 @@ use strict;
 use warnings;
 use v5.22;
 use List::Util qw( max );
-use diagnostics;
 
 sub draw_matrix {
     my ($matrix) = shift;
     my $answer;
     foreach my $y (@$matrix) {
         foreach my $x (@$y) {
-            if (defined( $x )) {
-                print $x;
-                $answer++ if ($x > 1);
-            } else {
-                print ".";
-            }
+            $answer++ if (defined( $x) && ($x > 1));
         }
-        print "\n";
     }
     return $answer;
 }
@@ -37,23 +30,26 @@ my @matrix = ();
 my ($rows, $columns) = (0, 0);
 foreach (@input) {
     my ($x1, $y1, $x2, $y2) = ( /(\d+),(\d+) -> (\d+),(\d+)/ );
-    say "input is ", join(", ", ($x1, $y1, $x2, $y2));
     if ($x1 == $x2) { # line is vertical
-        say "line is vertical";
         ($y1, $y2) = ($y2, $y1) if ($y1 > $y2); # swap so that $y1 < $y2
         for (my $y = $y1; $y <= $y2; $y++) {
             $matrix[$y][$x1]++;
         }
     }
     elsif ($y1 == $y2) { # line is horizontal
-        say "line is horizontal";
         ($x1, $x2) = ($x2, $x1) if ($x1 > $x2); # swap so that $x1 < $x2
         for (my $x = $x1; $x <= $x2; $x++) {
             $matrix[$y1][$x]++;
         }
     }
-    draw_matrix( \@matrix, $rows, $columns);
-    $wait = <STDIN>;
+    else { # line is diagonal
+        my $dx = ($x2 > $x1) ? 1 : -1;
+        my $dy = ($y2 > $y1) ? 1 : -1;
+        for (my $x = $x1, my $y = $y1; $x!=$x2 && $y!=$y2; $x+=$dx, $y+=$dy) {
+            $matrix[$y][$x]++;
+        }
+        $matrix[$y2][$x2]++; # for loop above stops just before reaching 2nd point
+    }
 }
 
 say draw_matrix( \@matrix );