Day 18: quite fast program, but slow to write

[aoc.git] / 2023 / 35.pl

diff --git a/2023/35.pl b/2023/35.pl
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+++ b/2023/35.pl
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+#!/usr/bin/perl -w
+
+use v5.38;
+use experimental 'multidimensional';
+$; = ';';
+
+my ($x, $y) = (1000, 1000);
+my ($xmin, $xmax, $ymin, $ymax) = (1000) x 4;
+my %dir = (
+       R => [ 1,  0 ],
+       D => [ 0,  1 ],
+       L => [ -1, 0 ],
+       U => [ 0, -1 ],
+);
+
+my %map;
+while (<>) {
+       my ($dir, $len, $col) = /^(.) (\d+) \(\#(\w+)\)/;
+       say "at $x,$y dir $dir len $len col $col";
+       while ($len--){
+               $x += $dir{$dir}->[0];
+               $y += $dir{$dir}->[1];
+               say "    at $x,$y len $len";
+
+               $xmax = $x if $xmax < $x;
+               $ymax = $y if $ymax < $y;
+               $xmin = $x if $xmin > $x;
+               $ymin = $y if $ymin > $y;
+
+               $map{$x,$y} = $col;
+       }
+}
+
+say "$xmin..$xmax x $ymin..$ymax";
+
+my $sum;
+for my $y ($ymin .. $ymax) {
+       my $in = 0;
+       my $from = 0;
+       for my $x ($xmin .. $xmax) {
+               if ($map{$x,$y}) {
+                       $sum++;
+                       if ($map{$x,$y-1} && $map{$x,$y+1}) {
+                               $in = !$in;
+                               $from = 0;
+                       } elsif ($map{$x,$y-1}) {
+                               if ($from == 1) {
+                                       $in = !$in;
+                                       $from = 0;
+                               } elsif ($from == 0) {
+                                       $from = -1;
+                               } else {
+                                       $from = 0;
+                               }
+                       } elsif ($map{$x,$y+1}) {
+                               if ($from == -1) {
+                                       $in = !$in;
+                                       $from = 0;
+                               } elsif ($from == 0) {
+                                       $from = 1;
+                               } else {
+                                       $from = 0;
+                               }
+                       }
+                       print '#';
+               } else {
+                       $sum++ if $in;
+                       print $map{$x,$y} || $in ? 'O' : '.';
+               }
+       }
+       print "\n";
+}
+
+
+asay $sum;
+