/// <summary>
/// Uses the Dijkstra Search Algorithm to find from one Vertex to another in the given Graph.
/// </summary>
/// <param name="graph"></param>
/// <param name="from"></param>
/// <param name="to"></param>
/// <returns></returns>
public static Vertex[] Search(Graph g, Vertex from, Vertex to)
{
//Initialize
Dictionary <Vertex, int> distances = new Dictionary <Vertex, int>();
Dictionary <Vertex, Vertex> predecessor = new Dictionary <Vertex, Vertex>();
bool found = false;
distances.Add(from, 0);
predecessor.Add(from, from);
foreach (Vertex v in g.Vertices)
{
if (!v.Equals(from))
{
distances.Add(v, Int32.MaxValue);
predecessor.Add(v, null);
}
}
PriorityQueue <Vertex> q = new PriorityQueue <Vertex>();
q.Insert(from, 0);
//Algorithm
while (q.Count != 0)
{
Vertex u = q.PopLowest();
//Goal Vertex found
if (u.Equals(to))
{
found = true;
break;
}
//Find all neighbors of u
Vertex[] neighbors = GraphHelper.FindAdjacentVertices(g, u);
//Analyse the neighbors and update their distances and predecessors accordingly
foreach (Vertex v in neighbors)
{
if (predecessor[v] != null)
{
//update distance
if (distances[u] + 1 < distances[v])
{
distances[v] = distances[u] + 1;
predecessor[v] = u;
q.InsertOverride(v, distances[u] + 1);
}
}
else
{
distances[v] = distances[u] + 1;
predecessor[v] = u;
q.InsertOverride(v, distances[u] + 1);
}
}
}
if (found)
{
return(GetPath(predecessor, to));
}
else
{
return(null);
}
}
private static void Main(string[] args)
{
GraphHelper graphHelper = new GraphHelper();
Graph graph = new Graph(GraphTypeEnum.Empty, 10);
Graph graph2 = new Graph(GraphTypeEnum.Complete, 10);
Graph graph3 = new Graph(GraphTypeEnum.Random, 4);
graphHelper.DepthFirstSearch(graph2);
//2,4
//2,3,4
//0,1,3
//1,2,4
//0,1,3
Graph andreea = new Graph(GraphTypeEnum.Empty, 5);
andreea.AdjacencyLists[0].Add(andreea.Nodes[2]);
andreea.AdjacencyLists[0].Add(andreea.Nodes[4]);
andreea.AdjacencyLists[1].Add(andreea.Nodes[2]);
andreea.AdjacencyLists[1].Add(andreea.Nodes[3]);
andreea.AdjacencyLists[1].Add(andreea.Nodes[4]);
andreea.AdjacencyLists[2].Add(andreea.Nodes[0]);
andreea.AdjacencyLists[2].Add(andreea.Nodes[1]);
andreea.AdjacencyLists[2].Add(andreea.Nodes[3]);
andreea.AdjacencyLists[3].Add(andreea.Nodes[1]);
andreea.AdjacencyLists[3].Add(andreea.Nodes[2]);
andreea.AdjacencyLists[3].Add(andreea.Nodes[4]);
andreea.AdjacencyLists[4].Add(andreea.Nodes[0]);
andreea.AdjacencyLists[4].Add(andreea.Nodes[1]);
andreea.AdjacencyLists[4].Add(andreea.Nodes[3]);
graphHelper.DepthFirstSearch(andreea);
graphHelper.GetConnectedComponents(andreea);
graphHelper.Euler(andreea);
graphHelper.Hamilton(andreea);
Graph graph4 = new Graph(GraphTypeEnum.Empty, 4);
graph4.AdjacencyLists[0].Add(graph4.Nodes[1]);
graph4.AdjacencyLists[1].Add(graph4.Nodes[0]);
graph4.AdjacencyLists[1].Add(graph4.Nodes[2]);
graph4.AdjacencyLists[2].Add(graph4.Nodes[1]);
graph4.AdjacencyLists[2].Add(graph4.Nodes[3]);
graph4.AdjacencyLists[3].Add(graph4.Nodes[2]);
graphHelper.DepthFirstSearch(graph4);
graphHelper.Euler(graph4);
Graph graph5 = new Graph(GraphTypeEnum.Empty, 4);
graph5.AdjacencyLists[0].Add(graph5.Nodes[1]);
graph5.AdjacencyLists[0].Add(graph5.Nodes[3]);
graph5.AdjacencyLists[1].Add(graph5.Nodes[0]);
graph5.AdjacencyLists[1].Add(graph5.Nodes[2]);
graph5.AdjacencyLists[2].Add(graph5.Nodes[1]);
graph5.AdjacencyLists[2].Add(graph5.Nodes[3]);
graph5.AdjacencyLists[3].Add(graph5.Nodes[2]);
graph5.AdjacencyLists[3].Add(graph5.Nodes[0]);
graph5.GetEdges();
graphHelper.DepthFirstSearch(graph5);
graphHelper.Euler(graph5);
graphHelper.Hamilton(graph5);
graph3.GetNumberOfEdges();
for (var i = 0; i < graph3.Nodes.Count; i++)
{
for (int j = 0; j < graph3.Nodes.Count; j++)
{
Console.Write(graph3.GetAdjacentyMatrix()[i, j] + " ");
}
Console.WriteLine();
}
graphHelper.DepthFirstSearch(graph3);
graph3.ConnectedComponents = graphHelper.GetConnectedComponents(graph3);
foreach (Edge graph3Bridge in graph3.Bridges)
{
Console.WriteLine(
graph3Bridge.ToString());
}
graphHelper.Euler(graph3);
graphHelper.Hamilton(graph3);
}
