From: Jan "Yenya" Kasprzak <kas@fi.muni.cz>
Date: Tue, 14 Dec 2021 07:32:22 +0000 (+0100)
Subject: 28.pl: code cleanup
X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?p=aoc2021.git;a=commitdiff_plain;h=6f0b62d78949e30c1d6443fe0548d9731158fe1e

28.pl: code cleanup
---

diff --git a/28.pl b/28.pl
index 5717759..d07c23c 100755
--- a/28.pl
+++ b/28.pl
@@ -1,41 +1,35 @@
 #!/usr/bin/perl -w
 
 use v5.16;
-use List::Util qw(sum0);
 
 chomp (my $tmpl = <>);
 scalar <>;
 
-my (%r1, %r2, %ins);
+my %rules;
 while (<>) {
 	chomp;
-	my ($s1, $s2, $d) = /([A-Z])/g;
-	$r1{"$s1$s2"} = "$s1$d";
-	$r2{"$s1$s2"} = "$d$s2";
-	$ins{"$s1$s2"} = $d;
+	my ($s1, $s2, $d) = /[A-Z]/g;
+	$rules{"$s1$s2"} = [ "$s1$d", "$d$s2", $d ];
 }
 
-my %count;
-my %p;
+my (%pairs, %count);
 for my $i (0 .. length($tmpl) - 2) {
-	$p{substr($tmpl, $i, 2)}++;
+	$pairs{substr($tmpl, $i, 2)}++;
 	$count{substr($tmpl, $i, 1)}++;
 }
 $count{substr($tmpl, -1, 1)}++;
 
 for (1 .. 40) {
-	my %p1;
-	for my $pair (keys %p) {
-		if ($r1{$pair}) {
-			$p1{$r1{$pair}} += $p{$pair};
-			$p1{$r2{$pair}} += $p{$pair};
-			$count{$ins{$pair}} += $p{$pair};
-		}
+	my %newp;
+	for my $pair (grep { $rules{$_} } keys %pairs) {
+		my $rule = $rules{$pair};
+		 $newp{ $rule->[0] } += $pairs{$pair};
+		 $newp{ $rule->[1] } += $pairs{$pair};
+		$count{ $rule->[2] } += $pairs{$pair};
 	}
-	%p = %p1;
+	%pairs = %newp;
 }
 
 my @count = sort { $a <=> $b } values %count;
-
 say $count[-1] - $count[0];