void Relax(EdgeWeightedDiagraph g, int v)
{
foreach (DirectedEdge e in g.AdjList(v))
{
int w = e.To();
if (distTo[w] < distTo[v] + e.Weight())
{
distTo[w] = distTo[v] + e.Weight();
edgeTo[w] = e;
}
}
}
//Bellman Ford has the complexity of O(VE)
public BellmanFordSP(EdgeWeightedDiagraph ewg, int source)
{
vertexNum = ewg.V();
distTo = new double[vertexNum];
edgeTo = new DirectedEdge[vertexNum];
for (int i = 0; i < vertexNum; i++)
{
distTo[i] = double.PositiveInfinity;
}
distTo[source] = 0.0;
}
public AcyclicSP(EdgeWeightedDiagraph ewg, int source)
{
edgeTo = new DirectedEdge[ewg.V()];
distTo = new double[ewg.V()];
for (int i = 0; i < ewg.V(); i++)
{
distTo[i] = double.PositiveInfinity;
}
distTo[source] = 0;
TopologicalOrder tlOrder = new TopologicalOrder(ewg);
foreach (int v in tlOrder.Order())
{
Relax(ewg, v);
}
}
public DijkstraSP(EdgeWeightedDiagraph g, int source)
{
vertexNumber = g.V();
distTo = new double[vertexNumber];
for (int i = 0; i < vertexNumber; i++)
{
distTo[i] = double.PositiveInfinity;
}
distTo[source] = 0.0;
edgeTo = new DirectedEdge[vertexNumber];
pq = new IndexMinPQ <double>(vertexNumber);
pq.Insert(source, 0.0);
while (!pq.IsEmpty())
{
int current = pq.DelMin();
Relax(g, current);
}
}
void Relax(EdgeWeightedDiagraph g, int v)
{
foreach (DirectedEdge e in g.AdjList(v))
{
int w = e.To();
double weight = e.Weight();
if (distTo[w] > distTo[v] + weight)
{
//relax
edgeTo[w] = e;
distTo[w] = distTo[v] + weight;
if (pq.Contains(w))
{
pq.ChangeKey(w, distTo[w]);
}
else
{
pq.Insert(w, distTo[w]);
}
}
}
}
void Relax(EdgeWeightedDiagraph ewg, int v)
{
}