static void Main(string[] args)
{
var graph = new CustomWeightedGraph();
graph.AddNode("A");
graph.AddNode("B");
graph.AddNode("C");
graph.AddNode("D");
graph.AddEdge("A", "B", 3);
graph.AddEdge("B", "C", 2);
graph.AddEdge("B", "D", 4);
graph.AddEdge("A", "C", 1);
graph.AddEdge("C", "D", 5);
graph.Print();
var from = "A";
var to = "D";
Console.WriteLine($"Shortest Distance {from}->{to} : {graph.GetShortestDistance(from, to)}");
Console.WriteLine($"Shortest Path {from}->{to}");
graph.GetShortestPath(from, to).Print();
Console.WriteLine($"Graph has cycle? : {graph.HasCycle()}");
Console.WriteLine("Creating Minimum Span Tree using Prim's Algorithm");
var minimumSpanTree = graph.MinimumSpanTree();
minimumSpanTree.Print();
}
public CustomWeightedGraph MinimumSpanTree()
{
// Prim's Algorithm
var minSpanTree = new CustomWeightedGraph();
var totalNodes = GetTotalNodes();
var nodes = new HashSet <Node>();
var edgesPriorityQueue = new C5.IntervalHeap <Edge>(new EdgeComp());
if (itemsMap.Count == 0)
{
return(minSpanTree); // Error Handling
}
var node = itemsMap.Values.First(); // Randomly pick the first node to add to Minimum Span Tree
nodes.Add(node);
minSpanTree.AddNode(node.label);
edgesPriorityQueue.AddAll(node.GetEdges());
while (nodes.Count < totalNodes)
{
var minEdge = edgesPriorityQueue.DeleteMax();
if (minSpanTree.ContainNode(minEdge.to.label) && minSpanTree.ContainNode(minEdge.from.label))
{
continue;
}
node = minEdge.to;
nodes.Add(node);
minSpanTree.AddNode(node.label);
minSpanTree.AddEdge(minEdge.from.label, minEdge.to.label, minEdge.weight);
edgesPriorityQueue.AddAll(node.GetEdges().Where(e => !minSpanTree.ContainNode(e.to.label)));
}
return(minSpanTree);
}