From 66b259d3a2fe9c6bd2c86d94ba3a666499e88a27 Mon Sep 17 00:00:00 2001
From: Yanick Champoux <yanick@babyl.ca>
Date: Sat, 9 Dec 2023 12:58:19 -0500
Subject: [PATCH] part 2

---
 2023/09/Part2.pm      | 10 ++++++++--
 2023/09/benchmark.pl  |  1 +
 2023/09/part1.t       |  2 +-
 2023/09/part2.t       |  2 +-
 2023/09/solutions.yml |  2 +-
 2023/benchmark.json   |  2 ++
 6 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/2023/09/Part2.pm b/2023/09/Part2.pm
index fd3b804..0009af7 100644
--- a/2023/09/Part2.pm
+++ b/2023/09/Part2.pm
@@ -9,12 +9,18 @@ use List::AllUtils qw/ all sum /;
 sub predict(@entries) {
     my $sum = 0;
 
+    my @first = ();
+
     until( all { !$_ } @entries ) {
-        $sum = $entries[0]-$sum;
+        push @first, $entries[0];
         @entries = map { $entries[$_]-$entries[$_-1] } 1..$#entries;
     }
 
-    return -$sum;
+    while(@first) {
+        $sum = pop( @first ) - $sum;
+    }
+
+    return $sum;
 }
 
 sub solution_2 ($input) {
diff --git a/2023/09/benchmark.pl b/2023/09/benchmark.pl
index 36ab17c..3ed103e 100644
--- a/2023/09/benchmark.pl
+++ b/2023/09/benchmark.pl
@@ -36,6 +36,7 @@ for my $part (@parts) {
         language  => 'perl',
         part      => $part->{part},
         time      => $res->cpu_a / $res->iters,
+        persec =>$res->iters/$res->cpu_a ,
         timestamp => DateTime->now->iso8601,
     };
     say to_json $result;
diff --git a/2023/09/part1.t b/2023/09/part1.t
index 7ff4614..f42e331 100644
--- a/2023/09/part1.t
+++ b/2023/09/part1.t
@@ -12,6 +12,6 @@ is Part1::predict(qw/0 3 6 9 12 15/) => 18;
 is Part1::predict(qw/1 3 6 10 15 21/) => 28;
 is Part1::predict(qw/10 13 16 21 30 45/) => 68;
 
-is Part1::solution_1($input) => 'TODO';
+is Part1::solution_1($input) => 1884768153;
 
 done_testing;
diff --git a/2023/09/part2.t b/2023/09/part2.t
index ec302b1..4d67482 100644
--- a/2023/09/part2.t
+++ b/2023/09/part2.t
@@ -19,6 +19,6 @@ is Part2::solution_2(<<END) => 2;
 END
 
 isnt Part2::solution_2($input) => -59;
-is Part2::solution_2($input) => 'TODO';
+is Part2::solution_2($input) => 1031;
 
 done_testing;
diff --git a/2023/09/solutions.yml b/2023/09/solutions.yml
index 6b32d69..6887c46 100644
--- a/2023/09/solutions.yml
+++ b/2023/09/solutions.yml
@@ -1,2 +1,2 @@
 1: 1884768153
-2: TODO
+2: 1031
diff --git a/2023/benchmark.json b/2023/benchmark.json
index b264505..aeaa9cd 100644
--- a/2023/benchmark.json
+++ b/2023/benchmark.json
@@ -16,3 +16,5 @@
 {"year":"2023","part":2,"language":"perl","day":"6","time":7.07875059716474e-06,"timestamp":"2023-12-06T15:43:13","persec":141267.867298578}
 {"language":"perl","persec":85.2380952380952,"year":"2023","timestamp":"2023-12-07T16:08:30","time":0.011731843575419,"part":1,"day":"7"}
 {"day":"7","part":2,"persec":85.2380952380952,"year":"2023","timestamp":"2023-12-07T16:08:43","time":0.011731843575419,"language":"perl"}
+{"persec":113.488372093023,"timestamp":"2023-12-09T17:57:35","language":"perl","year":"2023","time":0.00881147540983607,"day":"9","part":1}
+{"persec":109.783631232361,"timestamp":"2023-12-09T17:57:47","language":"perl","time":0.00910882604970008,"day":"9","part":2,"year":"2023"}