Add cc.

graph.rkt

@@ -35,7 +35,7 @@
 
            bfs bfs/generalized fewest-vertices-path
            dfs dfs/generalized
-           dag? tsort
+           dag? tsort cc
 
            graphviz)
 
@@ -175,6 +175,8 @@
     (g:dag? (gg g)))
   (define (tsort g)
     (g:tsort (gg g)))
+  (define (cc g)
+    (g:cc (gg g)))
 
   ;; 10 Graphviz
   (define (graphviz g #:output [output #f] #:colors [colors #f])
@@ -257,6 +259,7 @@
                         Any)]
   [dag? (-> Graph Boolean)]
   [tsort (-> Graph (Listof Any))]
+  [cc (-> Graph (Listof (Listof Any)))]
 
   ;; 10 Graphviz
   [graphviz (->* (Graph)
@@ -360,7 +363,9 @@
     (check-true (dag? (directed-graph '((a b) (b c)))))
     (check-false (dag? (directed-graph '((a b) (b a)))))
     (check-equal? (tsort (directed-graph '((a b) (b c) (a d) (d b))))
-                  '(a d b c)))
+                  '(a d b c))
+    (check-equal? (cc (undirected-graph '((a b) (b c) (d e))))
+                  '((e d) (a b c))))
 
   (test-case "10 Graphviz"
     (define g (directed-graph '((a b) (b c))))