/// <summary>
/// Returns all nodes in a directed graph with no edges pointing to it.
/// </summary>
/// <typeparam name="TNode">Type of nodes</typeparam>
/// <param name="graph">Graph with nodes</param>
/// <returns>List of top nodes</returns>
public static List <TNode> GetTopNodes <TNode>(this IGraph <TNode> graph)
{
List <TNode> nodes = graph.ToList();
for (int i = nodes.Count - 1; i >= 0; i--)
{
if (graph.Any(node => graph.IsEdge(node, nodes[i])))
{
nodes.RemoveAt(i);
}
}
return(nodes);
}
