First half of Year 2019

[aoc.git] / 2019 / 27.pl

diff --git a/2019/27.pl b/2019/27.pl
new file mode 100755 (executable)
index 0000000..6c4764c
--- /dev/null
+++ b/2019/27.pl
@@ -0,0 +1,51 @@
+#!/usr/bin/perl -w
+
+use v5.16;
+use Data::Dumper;
+use List::Util qw(any);
+
+my %rules;
+while (<>) {
+       chomp;
+       my ($srcs, $dstcount, $dst) = /(.*) => (\d+) (\w+)/;
+       my %srcs = reverse $srcs =~ /(\d+) (\w+)/g;
+       $rules{$dst} = {
+               count => $dstcount,
+               srcs  => \%srcs,
+       };
+}
+
+my (%want, %have);
+$want{FUEL} = 1;
+
+use List::Util qw(first);
+
+my $expanded;
+while (my $w = first { $_ ne 'ORE' && $want{$_} } keys %want) {
+       $expanded = 1;
+       my $r = $rules{$w};
+       my $rcount = int (($want{$w}+$r->{count}-1)/$r->{count});
+       say "want $want{$w} of $w, rule has $r->{count}, need $rcount rules";
+       if ($rcount * $r->{count} > $want{$w}) {
+               $have{$w} = $rcount * $r->{count} - $want{$w};
+       }
+       delete $want{$w};
+       for my $src (keys %{ $r->{srcs} }) {
+               my $need = $r->{srcs}->{$src} * $rcount;
+               if ($have{$src}) {
+                       if ($need >= $have{$src}) {
+                               $need -= $have{$src};
+                               delete $have{$src};
+                       } else {
+                               $have{$src} -= $need;
+                               next;
+                       }
+               }
+               $want{$src} += $need;
+       }
+       say "want: ", join(', ', map { "$want{$_} of $_" } keys %want);
+       say "have: ", join(', ', map { "$have{$_} of $_" } keys %have);
+       say "";
+}
+
+say $want{ORE};