some isolation of tasks

1 files changed, 10 insertions, 5 deletions

diff --git a/AoC2022/18/solver.lisp b/AoC2022/18/solver.lisp
index 778843d..91397ec 100644
--- a/AoC2022/18/solver.lisp
+++ b/AoC2022/18/solver.lisp
@@ -39,17 +39,22 @@
 (defconstant +neighbor-dirs+ '((1 0 0) (0 1 0) (0 0 1)
                                (-1 0 0) (0 -1 0) (0 0 -1)))
 
-(defun spread-steam (next outer-region cubes min-point max-point)
+(defun spread-steam (next allowedp)
   (loop for dir in +neighbor-dirs+
         for nbg = (mapcar #'+ next dir)
-        when (and (every #'<= min-point nbg max-point)
-                  (not (member nbg cubes :test #'equal))
-                  (not (member nbg outer-region :test #'equal)))
+        when (funcall allowedp nbg)
           collect nbg))
 
+(defun available-p (cubes min-point max-point)
+  (lambda (point)
+    (and (every #'<= min-point point max-point)
+         (not (member point cubes :test #'equal)))))
+
 (defun fill-outside (queue outer-region cubes min-point max-point)
   (reduce (lambda (out voxel)
-            (let ((next-queue (spread-steam voxel out cubes min-point max-point)))
+            (let ((next-queue (spread-steam voxel
+                                            (available-p
+                                             (append out cubes) min-point max-point))))
               (fill-outside next-queue
                             (append next-queue out)
                             cubes min-point max-point)))