private void addEdge(int src, int dst, int weight)
{
Tbdistance a = new Tbdistance(), b = new Tbdistance();
a.distance = b.distance = weight;
a.station1Id = b.station2id = src;
a.station2id = b.station1Id = dst;
routePool = routePool.Concat(new Tbdistance[] { a, b }).ToArray();
}
private void primAlgo()
{
output.Text = "";//the output to be returned and the end of the function
/*since it is diificult to push a element dynamicaly to a fixed array the variable selectedStationList
* maintains a list of user selected stations as string comma seperated and after collections split the string
* as an array to access each element by given index*/
String[] stationsIdsToBeConnected = selectedStationList.Split(',');
String[] visitedStationIds = new String[stationsIdsToBeConnected.Length];
//the first station is visited intitially, variable visitedStationIds maintains arrays of visited
//stations
visitedStationIds[0] = stationsIdsToBeConnected[0];
Tbdistance[] stageData = null;
int count = 1;//since one station is visited initially the count starts from 1
int totalWeight = 0;
while (count < stationsIdsToBeConnected.Length)//iterate until all the stations are connected/visited..
{
/*from list of all the interconnect (include both directional edges) routes
* connected to user given station, find set of routes where each edge's starting station is already visited
* but destination station is unvisited and a station which user has already defined*/
stageData = possibleRoutes.Where(
//check if any of ids of visited station match/not matching
r => visitedStationIds.Contains(r.station1Id.ToString()) &&
!visitedStationIds.Contains(r.station2id.ToString()) &&
stationsIdsToBeConnected.Contains(r.station1Id.ToString())).ToArray();
Tbdistance EdgeWithMinWeight = null;
int minWeight = int.MaxValue;//minWeight is set to int defined possible infinite
/*From resultant set edges find an edge with minimum distance/weight*/
foreach (Tbdistance d in stageData)
{
if (d.distance < minWeight)
{
EdgeWithMinWeight = d;
minWeight = d.distance.Value;
}
}
//mark the destination/connected station of edge with min weight to be visited
visitedStationIds[count] = EdgeWithMinWeight.station2id.ToString();
count++;
//increment the tota; weight of minimum spanning tree with discovered min weight
totalWeight += minWeight;
//In each iterartion display the edge with min weight...
output.Text += findStationName(EdgeWithMinWeight.station1Id.Value) + "<-->" + findStationName(EdgeWithMinWeight.station2id.Value) + " " + EdgeWithMinWeight.distance + Environment.NewLine;
}
output.Text += "Total weight " + totalWeight;
}