inDegree method
Returns the number of incoming directed edges for vertex
.
Returns null
if vertex
is not a graph vertex.
Implementation
int? inDegree(T vertex) {
if (!vertexExists(vertex)) {
return null;
}
var inDegree = 0;
for (final start in vertices) {
if (edgeExists(start, vertex)) {
++inDegree;
}
}
return inDegree;
}