I have been stuck on this question for days. Apparently I need to write a better algorithm to win the algorithm below. The below code is implemented from the famous Aima file. Is there any expert here who could guide me on how to win the algorithm?
(defun find-closest (list)
(x (car (array-dimensions list)))
(y (cadr (array-dimensions list)))
(let ((elems (aref list x y)))
(dolist (e elems)
(when (eq (type-of e) type)
(return-from find-closest (list x y)))) nil))
I tried implementing a DFS but failed and I do not quite know why. Below is my code.
(defun find-closest (list)
(let ((open (list list))
(closed (list))
(steps 0)
(expanded 0)
(stored 0))
(loop while open do
(let ((x (pop open)))
(when (finished? x)
(return (format nil "Found ~a in ~a steps.
Expanded ~a nodes, stored a maximum of ~a nodes." x steps expanded stored)))
(incf steps)
(pushnew x closed :test #'equal)
(let ((successors (successors x)))
(incf expanded (length successors))
(setq successors
(delete-if (lambda (a)
(or (find a open :test #'equal)
(find a closed :test #'equal)))
successors))
(setq open (append open successors))
(setq stored (max stored (length open))))))))