public void Run()
{
var nodeA = new DjikstraNode
{
Key = "A",
};
var nodeB = new DjikstraNode
{
Key = "B"
};
var nodeC = new DjikstraNode
{
Key = "C"
};
var nodeD = new DjikstraNode
{
Key = "D"
};
var nodeE = new DjikstraNode
{
Key = "E"
};
var nodeF = new DjikstraNode
{
Key = "F"
};
var nodeG = new DjikstraNode
{
Key = "G"
};
var nodeH = new DjikstraNode
{
Key = "H"
};
var tree = new List <DjikstraNode>
{
nodeA.AddConnection(nodeB, 8).AddConnection(nodeD, 5).AddConnection(nodeC, 2),
nodeB.AddConnection(nodeD, 2).AddConnection(nodeF, 13),
nodeC.AddConnection(nodeD, 2).AddConnection(nodeE, 5),
nodeD.AddConnection(nodeE, 1).AddConnection(nodeF, 6).AddConnection(nodeG, 3),
nodeE.AddConnection(nodeG, 1),
nodeF.AddConnection(nodeG, 2).AddConnection(nodeH, 3),
nodeG.AddConnection(nodeH, 6),
nodeH
};
FindShortestPath(tree, start: nodeA, end: nodeH);
}
public DjikstraNode AddConnection(DjikstraNode node, int cost, bool twoWay = true)
{
Edges.Add(new Edge
{
From = this,
To = node,
Cost = cost
});
if (twoWay)
{
node.AddConnection(this, cost, false);
}
return(this);
}
public void FindShortestPath(List <DjikstraNode> tree, DjikstraNode start, DjikstraNode end)
{
start.Distance.Value = 0;
DjikstraNode?currentNode = null;
while (currentNode != end)
{
var minDistance = double.PositiveInfinity;
for (int i = 0; i < tree.Count; i++)
{
if (!tree[i].Visited && minDistance > tree[i].Distance.Value)
{
minDistance = tree[i].Distance.Value;
currentNode = tree[i];
}
}
if (currentNode != null)
{
currentNode.Visited = true;
foreach (var edge in currentNode.Edges)
{
var newDistance = currentNode.Distance.Value + edge.Cost;
if (!edge.To.Visited && edge.To.Distance.Value > newDistance)
{
edge.To.Distance = new Distance
{
Value = newDistance,
ComingFrom = edge.From
};
}
}
}
}
// print result
var node = end;
while (node.Distance.ComingFrom != null)
{
Console.WriteLine($"{node.Key}-> Distance {node.Distance.Value}->Comming from {node.Distance.ComingFrom.Key}");
node = node.Distance.ComingFrom;
}
}