/// <summary>
/// (DIRECTED GRAPH) -Create a subgraph of an input graph between a start and end vertex (includes start and end vertex)
/// </summary>
/// <param name="startindex"></param>
/// <param name="endvertex"></param>
/// <param name="graph"></param>
/// <returns></returns>
public IDigraph CreateSubGraph(int startindex, int endvertex, IDigraph graph)
{
IDigraph subgraph = new Digraph(graph.VertexCount);
for (int i = 0; i < graph.VertexCount; i++)
{
subgraph.AddVertex();
}
for (int i = startindex; i <= endvertex; i++)
{
List <int> neighbors = (List <int>)graph.GetVertexNeighborsOut(i);
foreach (int neighbor in neighbors)
{
if (neighbor >= startindex && neighbor <= endvertex)
{
subgraph.AddEdge(i, neighbor);
}
}
}
return(subgraph);
}
/// <summary>
/// (DIRECTED GRAPH) -Create a copy of the directed graph that is reversed
/// </summary>
/// <param name="graph"></param>
/// <returns></returns>
public IDigraph ReverseGraph(IDigraph graph)
{
IDigraph reversegraph = new Digraph(graph.VertexCount);
for (int i = 0; i < graph.VertexCount; i++)
{
reversegraph.AddVertex();
}
for (int i = 0; i < graph.VertexCount; i++)
{
List <int> vertexneighbors = (List <int>)graph.GetVertexNeighborsOut(i);
//for each vertex that is connected, create a reverse edge with its neighbors
if (vertexneighbors.Count > 0)
{
foreach (int neighbor in vertexneighbors)
{
reversegraph.AddEdge(neighbor, i);
}
}
}
return(reversegraph);
}
