Day 3 part 2: even shorter solution

diff --git a/2025/06.pl b/2025/06.pl
index fd27cc9cec3576e15fd899364a643c46449cbf9c..f7d74ecb3152bec40f34b1928893d7f4883aa696 100755 (executable)
--- a/2025/06.pl
+++ b/2025/06.pl
@@ -7,9 +7,8 @@ sub search($in, $res, $len) {
        return $res if !$len--;
 
        for my $n (reverse 1 .. 9) {
-               my $re = $n . ('.' x $len);
-               next if $in !~ /$re/;
-               return search($in =~ s/^.*?$n//r, "$res$n", $len);
+               return search($1, "$res$n", $len)
+                       if $in =~ /$n(.{$len,})/;
        }
 }