2020, tracking

1 files changed, 28 insertions, 0 deletions

diff --git a/2020/day1/sumto.pl b/2020/day1/sumto.pl
new file mode 100644
index 0000000..931f5e2
--- /dev/null
+++ b/2020/day1/sumto.pl
@@ -0,0 +1,28 @@
+use strict;
+use warnings;
+use DDP;
+use Smart::Comments;
+
+open my $fh, '<', "input" or die "no input present, $!";
+chomp(my @nums = <$fh>);
+close $fh;
+
+@nums = sort { $a <=> $b } @nums;
+
+my $l_idx = 0;
+my $r_idx = $#nums;
+
+my $total = $nums[$l_idx] + $nums[$r_idx];
+
+while ($total != 2020) {
+
+    if ($total < 2020) {
+        $l_idx++; # total too low, increase
+    } else {
+        $r_idx--; # total too high, decrease
+    }
+
+    $total = $nums[$l_idx] + $nums[$r_idx];
+}
+
+print $nums[$l_idx] * $nums[$r_idx];