adjacentList

#+BEGIN_SRC emacs-lisp :results silent
  (defun make-adjacency-list (node links)
    "Make the adjacency list of a node by collecting
  all the nodes it's connected to in links."
    (loop for link in links
          if (= node (car link))
          collect (cdr link)))

  (defun make-adjacency-list-in-reverse (node links)
    "Make the reverse adjacency list of a node by collecting
  all the nodes connected to it in links."
    (loop for link in links
          if (= node (cdr link))
          collect (car link)))

  (defun make-adjacency-lists (nodes links)
    "Make adjacency lists given a graph's nodes and links
  by collecting the adjacency lists and reverse adjacency lists
  for each of the graph's nodes, removing any duplicates found."
    (let ((alists nil) the-nodes-alist)
      (loop for node in nodes
            do (setq the-nodes-alist
                     (remove-duplicates
                      (nconc (make-adjacency-list node links)
                             (make-adjacency-list-in-reverse node links)))
                     alists (nconc alists (list (cons node the-nodes-alist)))))
      alists))
#+END_SRC

#+BEGIN_SRC emacs-lisp
(make-adjacency-lists nodes graph-11-27-links)
#+END_SRC

#+RESULTS:
|  1 |  2 |  9 | 10 | 11 |    |    |   |
|  2 |  3 |  4 |  5 |  9 | 10 | 11 | 1 |
|  3 |  4 | 10 | 11 |  2 |    |    |   |
|  4 |  5 | 10 | 11 |  2 |  3 |    |   |
|  5 |  6 |  7 |  9 |  2 |  4 |    |   |
|  6 |  7 |  9 |  5 |    |    |    |   |
|  7 |  8 |  9 |  5 |  6 |    |    |   |
|  8 | 10 |  9 |  7 |    |    |    |   |
|  9 | 10 |  1 |  2 |  5 |  6 |  7 | 8 |
| 10 | 11 |  1 |  2 |  3 |  4 |  8 | 9 |
| 11 |  1 |  2 |  3 |  4 | 10 |    |   |

#+BEGIN_SRC emacs-lisp
(setq n '(make-adjacency-lists nodes graph-11-27-links)
   (mapcar (lambda (y) (cdr (x) n )))
      (mapcar (lambda (x) list (sort '> ))))  
#+END_SRC