adventofcode2022

commit b395818b35867113db7d5ceea12cd630c14f8db1
parent 4d1ebe018a49bcd81cb48be2f49552fb20551ba8
Author: Lukas Henkel <lh@entf.net>
Date:   Sat, 10 Dec 2022 09:18:23 +0100

Day 10 task 2

Diffstat:
M
src/day10.lisp
 | 
22
+++++++++++++++++++---
M
t/day10.lisp
 | 
12
++++++++++++

2 files changed, 31 insertions(+), 3 deletions(-)
diff --git a/src/day10.lisp b/src/day10.lisp
@@ -2,7 +2,10 @@
   (:use #:cl #:adventofcode2022))
 (in-package #:adventofcode2022/day10)
 
-(defun task1 (inputs)
+(defun sprite-covers-pixel-p (pixel sprite-pos)
+  (<= (abs (- sprite-pos pixel)) 1))
+
+(defun run-cpu (inputs &key (video-stream t))
   (loop with x = 1
         with i = 1
         for (op value) in inputs
@@ -18,11 +21,24 @@
                            (= j 140)
                            (= j 180)
                            (= j 220))
-                    sum (* j x))
+                    sum (* j x)
+                  do (format video-stream "~A"
+                             (if (sprite-covers-pixel-p (mod (1- j) 40) x)
+                                 #\#
+                                 #\.))
+                  when (= 0 (mod j 40))
+                    do (format video-stream "~%"))
         do (setf i ni)
         when (string= op "addx")
           do (incf x value)))
 
+(defun task1 (inputs)
+  (run-cpu inputs))
+
+(defun task2 (inputs)
+  (with-output-to-string (s)
+    (run-cpu inputs :video-stream s)))
+
 (define-day 10
     (:translate-input (lambda (line)
                         (let ((parts (uiop:split-string line :separator '(#\Space))))
@@ -30,4 +46,4 @@
                             (setf (cadr parts) (parse-integer (cadr parts))))
                           parts)))
   #'task1
-  nil)
+  #'task2)
diff --git a/t/day10.lisp b/t/day10.lisp
@@ -152,3 +152,15 @@ noop")
    (= 13140
       (run-task 10 1
                 (make-string-input-stream +testdata-day10+)))))
+
+(def-test day10-task2 ()
+  (is-true
+   (string= (run-task 10 2
+                      (make-string-input-stream +testdata-day10+))
+            "##..##..##..##..##..##..##..##..##..##..
+###...###...###...###...###...###...###.
+####....####....####....####....####....
+#####.....#####.....#####.....#####.....
+######......######......######......####
+#######.......#######.......#######.....
+")))