diff options
Diffstat (limited to 'AoC2022/08')
| -rw-r--r-- | AoC2022/08/solver.lisp | 30 |
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 |