/**
* Returns a list of vertices that are the direct predecessors of a specified vertex. If the
* graph is a multigraph, vertices may appear more than once in the returned list.
*
* <p>
* The method uses {@link Graph#incomingEdgesOf(Object)} to traverse the graph.
*
* @param g the graph to look for predecessors in
* @param vertex the vertex to get the predecessors of
* @param <V> the graph vertex type
* @param <E> the graph edge type
*
* @return a list of the vertices that are the direct predecessors of the specified vertex.
*/
public static List <V> predecessorListOf <V, E>(Graph <V, E> g, V vertex)
{
List <V> predecessors = new List <V>();
HashSet <E> edges = g.incomingEdgesOf(vertex);
foreach (E e in edges)
{
predecessors.Add(getOppositeVertex(g, e, vertex));
}
return(predecessors);
}
/**
* Check if a vertex has any direct predecessors.
*
* @param graph the graph to look for predecessors
* @param vertex the vertex to look for predecessors
* @param <V> the graph vertex type
* @param <E> the graph edge type
*
* @return true if the vertex has any predecessors, false otherwise
*/
public static bool vertexHasPredecessors <V, E>(Graph <V, E> graph, V vertex)
{
return(graph.incomingEdgesOf(vertex).Count != 0);
}
