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Add bfs/generalized.

master
Sergiu Ivanov 3 months ago
parent
commit
a40b1ec187
  1. 38
      graph.rkt

38
graph.rkt

@ -19,7 +19,8 @@
;;; https://stackoverflow.com/questions/65386334/racket-generic-graph-library-in-typed-racket
(module graph-wrapper racket
(require (prefix-in g: graph))
(require (prefix-in g: graph)
data/gen-queue/fifo)
(provide (struct-out graph) has-vertex? has-edge? vertex=? add-vertex! remove-vertex!
rename-vertex! add-edge! add-directed-edge! remove-edge!
remove-directed-edge! get-vertices in-vertices get-neighbors
@ -32,7 +33,7 @@
undirected-graph directed-graph
matrix-graph?
bfs fewest-vertices-path
bfs bfs/generalized fewest-vertices-path
dfs dfs/generalized
graphviz)
@ -115,6 +116,26 @@
;; 4.1 Breadth-first Search
(define (bfs g source)
(g:bfs (gg g) source))
(define (bfs/generalized
g
source
#:init-queue [init-queue (mk-empty-fifo)]
#:break [break? (λ (G source from to) #f)]
#:init [init void]
#:visit? [custom-visit?-fn (λ (G source from to) #f)]
#:discover [discover (λ (G s u v acc) acc)]
#:visit [visit (λ (G s v acc) acc)]
#:return [finish (λ (G s acc) acc)])
(g:bfs/generalized
(gg g)
source
#:init-queue init-queue
#:break break?
#:init init
#:visit? custom-visit?-fn
#:discover discover
#:visit visit
#:return finish))
(define (fewest-vertices-path G source target)
(g:fewest-vertices-path (gg G) source target))
@ -201,6 +222,15 @@
;; 4.1 Breadth-first Search
[bfs (-> Graph Any (Values (Mutable-HashTable Any Number)
(Mutable-HashTable Any Any)))]
[bfs/generalized (->* (Graph Any)
(#:init-queue Any ; TODO: Add a proper type.
#:break (-> Graph Any Any Any Boolean)
#:init (-> Graph Any Void)
#:visit? (-> Graph Any Any Any Boolean)
#:discover (-> Graph Any Any Any Any Any)
#:visit (-> Graph Any Any Any Any)
#:return (-> Graph Any Any Any))
Any)]
[fewest-vertices-path (-> Graph Any Any (U (Listof Any) False))]
;; 4.2 Depth-first Search
@ -301,6 +331,10 @@
(define-values (bfs-lens bfs-tree) (bfs (directed-graph '((a b) (b c))) 'a))
(check-equal? (hash->ordered-list bfs-lens) '((a . 0) (b . 1) (c . 2)))
(check-equal? (hash->ordered-list bfs-tree) '((a . #f) (b . a) (c . b)))
(check-equal? (bfs/generalized (directed-graph '((a b) (a c) (b d) (c d))) 'a)
(void))
(check-equal? (fewest-vertices-path (directed-graph '((a b) (b c) (c d))) 'a 'd)
'(a b c d))

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