public List <Belt> GetShortestPath(Belt startingBelt, Belt endingBelt)
{
try
{
if (endingBelt == null)
{
shortestPaths = new List <Belt>();
throw new Exception("end Belt is null-->test");
}
else
{
ContiniouslyFindShortestPath(startingBelt, endingBelt);
}
}
catch (NullReferenceException ex)
{
Console.WriteLine(ex.Message);
}
catch (Exception ex)
{
shortestPaths = null;
Console.WriteLine(ex.Message);
}
return(shortestPaths);
}
private void ContiniouslyFindShortestPath(Belt startingBelt, Belt endingBelt)
{
try
{
this.shortestPaths = new List <Belt>();
if (endingBelt != startingBelt)
{
if (endingBelt == null)
{
throw new Exception("end belt is null--> test");
}
GetShortestPath(startingBelt, endingBelt.Parent);
shortestPaths.Add(endingBelt);
Console.WriteLine("Vertex {0} weight: {1}", endingBelt.Name, endingBelt.Weight);
}
else
{
shortestPaths.Add(endingBelt);
Console.WriteLine("Vertex {0} weight: {1}", endingBelt.Name, endingBelt.Weight);
}
}
catch (NullReferenceException ex)
{
Console.WriteLine(ex.Message);
MessageBox.Show("Please complete path from check-in " + startingBelt + "until departure gate " + startingBelt);
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
public Dijkstra(Belt[] vertices, int[][] graph, int source)
{
this.vertices = new List <Belt>();
InitializeSource(vertices, vertices[source]);
// suppose we can go from A to B and from A to C,
//in this case we should give perioty to to the one with the lower weighted
PriorityQueue <Belt> queues = new PriorityQueue <Belt>();
for (int i = 0; i < vertices.Length; i++)
{
// add/ push the vertices and it weight
queues.Enqueue(vertices[i], vertices[i].Weight);
}
// triversing all other vertices
while (queues.Count > 0)
{
Belt u = queues.Dequeue();
this.vertices.Add(u);
//again traversing to all vertices
for (int v = 0; v < graph[Convert.ToInt32(u.Name)].Length; v++)
{
if (graph[Convert.ToInt32(u.Name)][v] > 0)
{
Relax(u, vertices[v], graph[Convert.ToInt32(u.Name)][v]);
//updating priority value since distance is changed
queues.UpdatePriority(vertices[v], vertices[v].Weight);
}
}
}
}
public void Relax(Belt u, Belt v, int weight)
{
if (v.Weight > u.Weight + weight)
{
v.Weight = u.Weight + weight;
v.Parent = u;
}
}
/* we need to initialize the source to do that we should consider the following
* we need lsit of vertics of type belt becuase belt has got the vertices
* start point/ vertics
* ---------------------------------------------------
* vetices| wieght | Prevoius vertoice
* ---------------------------------------------------
* A | 0 | parent ==null
* B | 5 | parent = A
* C | 2 | parent = A
*
*/
public void InitializeSource(Belt[] vertices, Belt startVertice)
{
//loop throught he lsit of given vertices
foreach (Belt v in vertices)
{
//get assign the weight--> initially the wight of all vertices ins infinity
v.Weight = int.MaxValue;
// parent a --> a you remain in the a
v.Parent = null;
}
// the wright of starting Vertice is nothing but 0 as per the Dijkstra algor
startVertice.Weight = 0;
}