module Johnson:
Parameters: 

module HVV:Hashtbl.S
with type key = (G.V.t * G.V.t)
val all_pairs_shortest_paths : Path.G.t > W.t HVV.t
all_pairs_shortest_paths g
computes the distance of shortest
path between all pairs of vertices in g
. They are returned as
a hash table mapping each pair of vertices to their
distance. If g
contains a negativecycle, raises
NegativeCycle l
where l
is such a cycle.
Complexity: at most O(VElog(V))