Year 2015

[aoc.git] / 2015 / 45.pl

diff --git a/2015/45.pl b/2015/45.pl
new file mode 100755 (executable)
index 0000000..dd6e8d6
--- /dev/null
+++ b/2015/45.pl
@@ -0,0 +1,31 @@
+#!/usr/bin/perl -w
+
+use v5.16;
+use strict;
+
+my %regs = ( a => 0, b => 0 );
+my @code = map { chomp; [ split /[ ,+]+/ ] } <>;
+my $ip = 0;
+while ($ip < @code) {
+       my ($ins, $v1, $v2) = @{ $code[$ip] };
+       say "$ip: ", join(' ', @{ $code[$ip] }), " a=$regs{a} b=$regs{b}";
+       if ($ins eq 'hlf') {
+               $regs{$v1} = int($regs{$v1}/2);
+       } elsif ($ins eq 'tpl') {
+               $regs{$v1} *= 3;
+       } elsif ($ins eq 'inc') {
+               $regs{$v1}++;
+       } elsif ($ins eq 'jmp') {
+               $ip += $v1 - 1;
+       } elsif ($ins eq 'jie') {
+               $ip += $v2 - 1 if $regs{$v1} % 2 == 0;
+       } elsif ($ins eq 'jio') {
+               $ip += $v2 - 1 if $regs{$v1} == 1;
+       } else {
+               say "Invalid insn $ins";
+       }
+       $ip++;
+}
+
+say "ip=$ip";
+say $regs{b};