adventofcode2022

commit 52531e8425521cbc2d23fe5871045f138c6315d3
parent 95accd44e0c22624d279fa1ef155f93460230761
Author: Lukas Henkel <lh@entf.net>
Date:   Tue, 13 Dec 2022 22:47:04 +0100

Day 13 task 2

Diffstat:
M
src/day13.lisp
 | 
12
+++++++++++-
M
t/day13.lisp
 | 
6
++++++

2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/src/day13.lisp b/src/day13.lisp
@@ -41,6 +41,16 @@
         when (compare-lists a b)
           sum i))
 
+(defun task2 (inputs)
+  (let ((divider-packets (list #(#(2)) #(#(6)))))
+    (apply #'*
+           (loop for packet in (-> (remove-if #'null inputs)
+                                 (append (copy-seq divider-packets))
+                                 (sort (lambda (a b) (compare-lists a b))))
+                 for i from 1
+                 when (find packet divider-packets :test 'eq)
+                   collect i))))
+
 (define-day 13
     (:translate-input (lambda (line)
                         (if (= (length line) 0)
@@ -51,4 +61,4 @@
                               (str:replace-all "," " ")
                               (read-from-string)))))
   #'task1
-  nil)
+  #'task2)
diff --git a/t/day13.lisp b/t/day13.lisp
@@ -47,3 +47,9 @@
    (= 13
       (run-task 13 1
                 (make-string-input-stream +testdata-day13+)))))
+
+(def-test day13-task2 ()
+  (is-true
+   (= 140
+      (run-task 13 2
+                (make-string-input-stream +testdata-day13+)))))