(defun ge-to-al (graph)
(mapcar #'(lambda (x) (list x (adj-list graph x))) (car graph))
)
(defun adj-list (graph node)
(apply #'append (mapcar #'(lambda (x) (neighbor x node)) (second graph)))
)
(defun neighbor (pair node)
(cond
((eql node (first pair)) (list (second pair)))
((eql node (second pair)) (list (first pair)))
(t ())
)
)