Day 13: off-by-one errors, quite ugly

diff --git a/2023/25.pl b/2023/25.pl
new file mode 100755 (executable)
index 0000000..24e02dd
--- /dev/null
+++ b/2023/25.pl
@@ -0,0 +1,55 @@
+#!/usr/bin/perl -w
+
+use v5.38;
+use experimental 'multidimensional', 'for_list', 'builtin';
+use builtin 'indexed';
+use List::Util;
+use Y::AoC::Task;
+$; = ';';
+# t;
+
+$/ = "\n\n";
+
+my $sum;
+MAP:
+while (<>) {
+       chomp;
+       my @map = map { [ split // ] } split /\n/, $_;
+
+       say "============ $#{ $map[0] } x $#map ==========";
+       COL:
+       for my $r1 (1 .. $#{ $map[0] }) {
+               say "Trying col $r1";
+               for my $x (0 .. $r1) {
+                       my $x1 = 2*$r1-$x-1;
+                       say "col $x vs $x1";
+                       next if $x1 > $#{ $map[0] };
+                       for my $y (0 .. $#map) {
+                               next COL if $map[$y][$x] ne $map[$y][$x1];
+                       }
+               }
+               say "X match at $r1";
+               $sum += $r1;
+               next MAP;
+       }
+       ROW:
+       for my $r1 (1 .. $#map) {
+               say "Trying row $r1";
+               for my $y (0 .. $r1) {
+                       my $y1 = 2*$r1-$y-1;
+                       say "row $y vs $y1";
+                       next if $y1 > $#map;
+                       for my $x (0 .. $#{ $map[0] }) {
+                               next ROW if $map[$y][$x] ne $map[$y1][$x];
+                       }
+               }
+               say "Y match at $r1";
+               $sum += 100*$r1;
+               next MAP;
+       }
+       die "No match at $.";
+}
+
+say $sum;
+
+

diff --git a/2023/26.pl b/2023/26.pl
new file mode 100755 (executable)
index 0000000..e577106
--- /dev/null
+++ b/2023/26.pl
@@ -0,0 +1,98 @@
+#!/usr/bin/perl -w
+
+use v5.38;
+use experimental 'multidimensional', 'for_list', 'builtin';
+use builtin 'indexed';
+use List::Util;
+use Y::AoC::Task;
+$; = ';';
+# t;
+
+$/ = "\n\n";
+
+my $sum;
+MAP:
+while (<>) {
+       chomp;
+       my @map = map { [ split // ] } split /\n/, $_;
+       
+       my $n;
+       COL:
+       for my $r1 (1 .. $#{ $map[0] }) {
+               say "Trying col $r1";
+               for my $x (0 .. $r1) {
+                       my $x1 = 2*$r1-$x-1;
+                       say "col $x vs $x1";
+                       next if $x1 > $#{ $map[0] };
+                       for my $y (0 .. $#map) {
+                               next COL if $map[$y][$x] ne $map[$y][$x1];
+                       }
+               }
+               say "X match at $r1";
+               $n += $r1;
+               goto OUT;
+       }
+       ROW:
+       for my $r1 (1 .. $#map) {
+               say "Trying row $r1";
+               for my $y (0 .. $r1) {
+                       my $y1 = 2*$r1-$y-1;
+                       say "row $y vs $y1";
+                       next if $y1 > $#map;
+                       for my $x (0 .. $#{ $map[0] }) {
+                               next ROW if $map[$y][$x] ne $map[$y1][$x];
+                       }
+               }
+               say "Y match at $r1";
+               $n = 100*$r1;
+               goto OUT;
+       }
+       OUT:
+       
+       for my $sx (0 .. $#{ $map[0] }) {
+               for my $sy (0 .. $#map) {
+                       my $old = $map[$sy][$sx];
+                       $map[$sy][$sx] = ($old eq '.') ? '#' : '.';
+                       say "######################### $sx,$sy $old $map[$sy][$sx]";
+       say "============ $#{ $map[0] } x $#map ==========";
+       COL:
+       for my $r1 (1 .. $#{ $map[0] }) {
+               next if $n == $r1;
+               say "Trying col $r1";
+               for my $x (0 .. $r1) {
+                       my $x1 = 2*$r1-$x-1;
+                       say "col $x vs $x1";
+                       next if $x1 > $#{ $map[0] };
+                       for my $y (0 .. $#map) {
+                               next COL if $map[$y][$x] ne $map[$y][$x1];
+                       }
+               }
+               say "X match at $r1";
+               $sum += $r1;
+               next MAP;
+       }
+       ROW:
+       for my $r1 (1 .. $#map) {
+               next if $n == 100*$r1;
+               say "Trying row $r1";
+               for my $y (0 .. $r1) {
+                       my $y1 = 2*$r1-$y-1;
+                       say "row $y vs $y1";
+                       next if $y1 > $#map;
+                       for my $x (0 .. $#{ $map[0] }) {
+                               next ROW if $map[$y][$x] ne $map[$y1][$x];
+                       }
+               }
+               say "Y match at $r1";
+               $sum += 100*$r1;
+               next MAP;
+       }
+                       $map[$sy][$sx] = $old;
+               }
+       }
+       die "No match at $.";
+}
+
+say $sum;
+
+