graph :: Digraph :: incoming_arcs
u
.If u
is not in this graph, an empty array is returned.
var g = new HashDigraph[Int]
g.add_arc(1, 3)
g.add_arc(2, 3)
for arc in g.incoming_arcs(3) do
assert g.is_predecessor(arc[0], arc[1])
end
# Returns the incoming arcs of vertex `u`.
#
# If `u` is not in this graph, an empty array is returned.
#
# ~~~
# var g = new HashDigraph[Int]
# g.add_arc(1, 3)
# g.add_arc(2, 3)
# for arc in g.incoming_arcs(3) do
# assert g.is_predecessor(arc[0], arc[1])
# end
# ~~~
fun incoming_arcs(u: V): Collection[Array[V]]
do
if has_vertex(u) then
return [for v in predecessors(u) do [v, u]]
else
return new Array[Array[V]]
end
end
lib/graph/digraph.nit:292,2--311,4