Add dijkstra.

graph.rkt

@@ -39,7 +39,7 @@
 
            min-st-kruskal max-st-kruskal min-st-prim max-st-prim
 
-           bellman-ford
+           bellman-ford dijkstra
 
            graphviz)
 
@@ -199,6 +199,8 @@
   ;; 6 Single-source Shortest Paths
   (define (bellman-ford g source)
     (g:bellman-ford (gg g) source))
+  (define (dijkstra g source)
+    (g:dijkstra (gg g) source))
 
   ;; 10 Graphviz
   (define (graphviz g #:output [output #f] #:colors [colors #f])
@@ -294,6 +296,8 @@
   ;; Single-source Shortest Paths
   [bellman-ford (-> Graph Any (Values (Mutable-HashTable Any Number)
                                       (Mutable-HashTable Any Any)))]
+  [dijkstra (-> Graph Any (Values (Mutable-HashTable Any Number)
+                                  (Mutable-HashTable Any Any)))]
 
   ;; 10 Graphviz
   [graphviz (->* (Graph)
@@ -425,6 +429,12 @@
     (check-equal? (hash->ordered-list bf-dists)
                   '((a . 0) (b . 1) (c . 2) (d . 4)))
     (check-equal? (hash->ordered-list bf-pred)
+                  '((a . #f) (b . a) (c . a) (d . b)))
+
+    (define-values (dj-dists dj-pred) (dijkstra g0 'a))
+    (check-equal? (hash->ordered-list dj-dists)
+                  '((a . 0) (b . 1) (c . 2) (d . 4)))
+    (check-equal? (hash->ordered-list dj-pred)
                   '((a . #f) (b . a) (c . a) (d . b))))
 
   (test-case "10 Graphviz"