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Add johnson.

master
Sergiu Ivanov 3 months ago
parent
commit
709c1360b9
  1. 25
      graph.rkt

25
graph.rkt

@ -40,7 +40,7 @@
min-st-kruskal max-st-kruskal min-st-prim max-st-prim
bellman-ford dijkstra dag-shortest-paths
floyd-warshall transitive-closure
floyd-warshall transitive-closure johnson
graphviz)
@ -210,6 +210,8 @@
(g:floyd-warshall (gg g)))
(define (transitive-closure g)
(g:transitive-closure (gg g)))
(define (johnson g)
(g:johnson (gg g)))
;; 10 Graphviz
(define (graphviz g #:output [output #f] #:colors [colors #f])
@ -313,6 +315,7 @@
;; 7 All-pairs Shortest Paths
[floyd-warshall (-> Graph (Mutable-HashTable (List Any Any) Number))]
[transitive-closure (-> Graph (Mutable-HashTable (List Any Any) Boolean))]
[johnson (-> Graph (Mutable-HashTable (List Any Any) Number))]
;; 10 Graphviz
[graphviz (->* (Graph)
@ -495,7 +498,25 @@
((b d) . #t)
((b b) . #t)
((d b) . #f)
((a b) . #t))))
((a b) . #t)))
(check-equal? (hash->ordered-list (johnson g0))
'(((a d) . 4)
((c c) . 0)
((b a) . +inf.0)
((a a) . 0)
((d c) . +inf.0)
((a c) . 2)
((c b) . +inf.0)
((d d) . 0)
((c a) . +inf.0)
((b c) . +inf.0)
((d a) . +inf.0)
((c d) . 3)
((b d) . 3)
((b b) . 0)
((d b) . +inf.0)
((a b) . 1))))
(test-case "10 Graphviz"
(define g (directed-graph '((a b) (b c))))

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