private void Relax(WeightedDiGraph <T> G, T v)
{
foreach (var e in G.Adj(v))
{
T w = e.To();
if (distTo[w] > distTo[v] + e.Weight)
{
distTo[w] = distTo[v] + e.Weight;
edgeTo[w] = e;
if (!onQueue[w])
{
queue.Enqueue(w);
onQueue[w] = true;
}
}
if (cost++ % G.V() == 0)
{
FindNegativeCycle();
if (HasNegativeCycle())
{
return; // found a negative cycle
}
}
}
}
public Dijkstra(WeightedDiGraph G, int s)
{
this.s = s;
int V = G.V();
marked = new bool[V];
edgeTo = new Edge[V];
cost = new double[V];
for (var i = 0; i < V; ++i)
{
cost[i] = Double.MaxValue;
}
cost[s] = 0;
pq = new IndexMinPQ <Double>(V);
pq.Insert(s, 0);
while (!pq.IsEmpty)
{
var v = pq.DelMin();
marked[v] = true;
foreach (var e in G.adj(v))
{
Relax(G, e);
}
}
}
public TopologicalSortShortestPath(WeightedDiGraph G, int s)
{
this.s = s;
int V = G.V();
marked = new bool[V];
edgeTo = new Edge[V];
cost = new double[V];
for (var i = 0; i < V; ++i)
{
cost[i] = Double.MaxValue;
}
cost[s] = 0;
DepthFirstPostOrder dfo = new DepthFirstPostOrder(G.ToDiGraph());
foreach (var v in dfo.PostOrder())
{
foreach (var e in G.adj(v))
{
Relax(G, e);
}
}
}
public void Test()
{
WeightedDiGraph G = GraphGenerator.directedEdgeWeightedGraph();
Dijkstra dijkstra = new Dijkstra(G, 0);
for (var v = 1; v < G.V(); ++v)
{
if (!dijkstra.HasPathTo(v))
{
Console.WriteLine("Path not found for {0}", v);
continue;
}
IEnumerable <Edge> path = dijkstra.PathTo(v);
console.WriteLine(ToString(path));
Console.WriteLine(ToString(path));
}
}
public void Test()
{
WeightedDiGraph G = GraphGenerator.directedEdgeWeightedGraph();
BellmanFulkerson BellmanFulkerson = new BellmanFulkerson(G, 0);
for (var v = 1; v < G.V(); ++v)
{
if (!BellmanFulkerson.HasPathTo(v))
{
Console.WriteLine("Path not found for {0}", v);
continue;
}
IEnumerable <Edge> path = BellmanFulkerson.PathTo(v);
console.WriteLine(ToString(path));
Console.WriteLine(ToString(path));
}
}
public BellmanFulkerson(WeightedDiGraph G, int s)
{
this.s = s;
var V = G.V();
cost = new double[V];
for (var v = 0; v < V; ++v)
{
cost[v] = Double.MaxValue;
}
edgeTo = new Edge[V];
cost[s] = 0;
for (var j = 0; j < V; ++j)
{
for (var v = 0; v < V; ++v)
{
foreach (var e in G.adj(v))
{
Relax(G, e);
}
}
}
negativeCycles = false;
for (var v = 0; v < V; ++v)
{
foreach (var e in G.adj(v))
{
if (Relax(G, e))
{
negativeCycles = true;
}
}
}
}
