my code of missionaries and cannibals

helloi m sending a small portion of my code for missionaries and cannibals in lisp....my code determines only one path from start to goal state...can anyone help me to write a code in lisp which determines all the possible paths to the goal state.reply soon.thanksbye. 
>(setf start '(3 3 1 0 0 0))

(3 3 1 0 0 0)

 

>(setf finish '(0 0 0 3 3 1))

(0 0 0 3 3 1)

 

>(setf all-actions '((1 0 1) (0 1 1) (2 0 1) (0 2 1) (1 1 1)))

((1 0 1) (0 1 1) (2 0 1) (0 2 1) (1 1 1))   

 

>(defun mcp (start finish &optional

                     (queue (list (list start))))

   (cond ((endp queue) nil)

         ((equal finish (first (first queue)))

          (reverse (first queue)))

         (t (mcp start finish

              (append (tree (first queue))

                (rest queue))))))

MCP                       

 

>(defun tree (path)

   (print (reverse path))

   (setf nodes (get-nodes path))

   (mapcar #'(lambda (new-node) (cons new-node path))

     (filter-nodes nodes path)))

TREE        

      

>(defun get-nodes (path)

   (if (= 1 (third (first path)))

      (first-approach (first path) all-actions)

      (second-approach (first path) all-actions)))

GET-NODES      

     

>(defun filter-nodes (nodes path)

   (cond ((endp nodes) nil)

         ((and (not (endp (first nodes)))

               (not (member (first nodes) path :test #'equal)))

          (cons (first nodes)

            (filter-nodes (rest nodes) path)))

         (t (filter-nodes (rest nodes) path))))

FILTER-NODES       

 

Output:

((3 3 1 0 0 0) (2 2 0 1 1 1) (3 2 1 0 1 0) (3 0 0 0 3 1) (3 1 1 0 2 0)

 (1 1 0 2 2 1) (2 2 1 1 1 0) (0 2 0 3 1 1) (0 3 1 3 0 0) (0 1 0 3 2 1)

 (0 2 1 3 1 0) (0 0 0 3 3 1))       


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