我在为这个程序生成正确的输出时遇到了一些问题。我的输出几乎是正确的，但缺少一些步骤。我的代码如下：
(defun kt (x y m n) ;set the board
(setq totalmoves (* m n)) ;find the total moves
(setq steps 1) ;count steps
(setq lst (list (list x y))) ;list visited with initial points
(findPath x y totalmoves steps m n lst) ;start tour with initial points
)
(defun findPath (x y totalMoves steps m n lst)
(cond
((null lst) NIL)
((= steps totalMoves) lst) ;if steps equals than total moves, then solution is complete
;try to solve the rest recursively
;1- down and right
((canMove (+ x 2) (+ y 1) m n lst)
(findPath (+ x 2) (+ y 1) totalMoves (+ steps 1) m n (appendList (+ x 2) (+ y 1) lst))
)
;2- right and down
((canMove (+ x 1) (+ y 2) m n lst)
(findPath (+ x 1) (+ y 2) totalMoves (+ steps 1) m n (appendList (+ x 1) (+ y 2) lst))
)
;3- right ups
((canMove (- x 1) (+ y 2) m n lst)
(findPath (- x 1) (+ y 2) totalMoves (+ steps 1) m n (appendList(- x 1) (+ y 2) lst))
)
;4- up and right
((canMove(- x 2) (+ y 1) m n lst)
(findPath(- x 2) (+ y 1) totalMoves (+ steps 1) m n (appendList(- x 2) (+ y 1) lst))
)
;5 - up and left
((canMove(- x 2) (- y 1) m n lst)
(findPath(- x 2) (- y 1) totalMoves (+ steps 1) m n (appendList(- x 2) (- y 1) lst))
)
;6- left and up
((canMove(- x 1) (- y 2) m n lst)
(findPath(- x 1) (- y 2) totalMoves (+ steps 1) m n (appendList(- x 1) (- y 2) lst))
)
;7- left and down
((canMove(+ x 1) (- y 2) m n lst)
(findPath(+ x 1) (- y 2) totalMoves (+ steps 1) m n (appendList(+ x 1) (- y 2) lst))
)
;8- down and left
((canMove(+ x 2) (- y 1) m n lst)
(findPath(+ x 2) (- y 1) totalMoves (+ steps 1) m n (appendList(+ x 2) (- y 1) lst))
)
(t
(findPath (car(car(reverse lst))) (car(cdr(car(reverse lst)))) totalMoves steps m n (reverse(cdr (reverse lst))))
)
)
)
(defun appendList (x y lst)
(setq lst (reverse(append (list (list x y)) (reverse lst))))
)
(defun check-visited (x y lst)
(cond
((null lst) 1) ;if nth else to check in list
((equal (list x y) (car lst)) NIL) ;check if curr is visited
((check-visited x y (cdr lst))) ;recurse
)
)
(defun canMove (x y m n lst)
(if (and (<= 1 x) ;for the correct state, all conditions below must be met
(<= x m) ;height is more than or equal to x
(<= 1 y)
(<= y n) ;width is more than or equal to y
(equal (check-visited x y lst) 1)
)
1 NIL ;if all above conds are true, return true else return nil
)
)
测试代码是
kt 1 1 5 5
输出是((1 1) (3 2) (5 3) (4 5) (2 4) (1 2) (3 3) (5 4) (3 5) (1 4) (2 2) (4 3) (5 5) (3 4) (1 5) (2 3) (4 4) (2 5) (1 3) (2 1) (4 2))
这里列出了 21 个步骤，但它应该有 25 个。