X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?p=aoc2020.git;a=blobdiff_plain;f=37.pl;fp=37.pl;h=97b548719c14c37ba329c23937683ac72323e63b;hp=0000000000000000000000000000000000000000;hb=bafab1d5fe18827b4d193a33372d0b22bb6d0c67;hpb=7a9b53e9740a2be6eac4410c791a6100a116ac3c

diff --git a/37.pl b/37.pl
new file mode 100755
index 0000000..97b5487
--- /dev/null
+++ b/37.pl
@@ -0,0 +1,49 @@
+#!/usr/bin/perl -w
+
+use strict;
+
+my %rules;
+my %subrules;
+my %final;
+
+while (<>) {
+	chomp;
+	last if /^$/;
+	my ($id, $rest) = /\A(\d+): (.*)\z/;
+	if ($rest =~ /"(.)"/) {
+		$final{$id} = $1;
+		next;
+	}
+	my @alts;
+	my @subalts;
+	for my $seq (split /\|/, $rest) {
+		push @alts, [ $seq =~ /(\d+)/g ];
+		push @subalts, ($seq =~ /(\d+)/g);
+	}
+	$rules{$id} = \@alts;
+	$subrules{$id} = \@subalts;
+}
+
+while (keys %rules) {
+	RULE:
+	for my $id (keys %rules) {
+		for my $subr (@{ $subrules{$id} }) {
+			next RULE if !defined $final{$subr};
+		}
+		$final{$id} = '(?:(?:' . join(')|(?:', map {
+			join('', map { $final{$_} } @$_)
+			} @{ $rules{$id} }) .'))';
+		print "\$final{$id} = $final{$id}\n";
+		delete $rules{$id};
+	}
+}
+
+my $re = '\A'.$final{0}.'\z';
+
+my $count = 0;
+while (<>) {
+	chomp;
+	$count++ if ($_ =~ /$re/);
+}
+
+print "$count matched\n";