Include arrow dependency

1 files changed, 14 insertions, 16 deletions

diff --git a/AoC2022/08/solver.lisp b/AoC2022/08/solver.lisp
index 166e56b..9f5c754 100644
--- a/AoC2022/08/solver.lisp
+++ b/AoC2022/08/solver.lisp
@@ -1,4 +1,4 @@
-(ql:quickload '(fiveam uiop))
+(ql:quickload '(fiveam uiop arrows))
 
 (defun coord-x-minor (width height)
   (lambda (x y)
@@ -14,6 +14,14 @@
                  (lambda (x) (- (char-code x) 48))
                  (apply #'concatenate 'string data)))))
 
+(defun line-of-sight (direction x y width height)
+  (let ((location (coord-x-minor width height)))
+    (case direction
+      (right    (loop for l from (1+ x) below width  collect (funcall location l y)))
+      (bottom   (loop for l from (1+ y) below height collect (funcall location x l)))
+      (left (loop for l downfrom (1- x) to 0         collect (funcall location l y)))
+      (top  (loop for l downfrom (1- y) to 0         collect (funcall location x l))))))
+
 (defun solver-p1 (filename)
   (multiple-value-bind (width height forest-arr) (forest (uiop:read-file-lines filename))
     (let ((visibility-mask (make-array (* width height) :initial-element nil))
@@ -36,14 +44,6 @@
         (toggle-visibility width height #'location-y t))
       (loop for v across visibility-mask counting v))))
 
-(defun line-of-sight (direction x y width height)
-  (let ((location (coord-x-minor width height)))
-    (case direction
-      (right    (loop for l from (1+ x) below width  collect (funcall location l y)))
-      (bottom   (loop for l from (1+ y) below height collect (funcall location x l)))
-      (left (loop for l downfrom (1- x) to 0         collect (funcall location l y)))
-      (top  (loop for l downfrom (1- y) to 0         collect (funcall location x l))))))
-
 (defun solver-p2 (filename)
   (multiple-value-bind (width height forest-arr) (forest (uiop:read-file-lines filename))
     (let ((score (make-array (* width height)))
@@ -56,13 +56,11 @@
         (dotimes (y height)
           (dotimes (x width)
             (let ((base (aref forest-arr (funcall location-x x y))))
-              (flet ((sight (direction) (line-of-sight direction x y width height)))
-                (setf (aref score (funcall location-x x y))
-                      (*
-                       (score-direction base (sight 'right))
-                       (score-direction base (sight 'bottom))
-                       (score-direction base (sight 'left))
-                       (score-direction base (sight 'top))))))))
+              (arrows:->> '(right left top bottom)
+                          (mapcar (lambda (direction)
+                                    (score-direction base (line-of-sight direction x y width height))))
+                          (apply #'* )
+                          (setf (aref score (funcall location-x x y)))))))
         (loop for v across score maximize v)))))
 
 (fiveam:test solutions