public Dijstra(GridWorld G, int s)
{
world = G;
this.s = s;
int V = G.VertexCount;
marked = new bool[V];
edgeTo = new DirectedWeightedEdge[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);
}
}
}
private void Relax(GridWorld G, DirectedWeightedEdge e)
{
int v = e.From();
int w = e.To();
if (cost[w] > cost[v] + e.Weight)
{
cost[w] = cost[v] + e.Weight;
edgeTo[w] = e;
if (!pq.Contains(w))
{
pq.Insert(w, cost[w]);
}
else
{
pq.DecreaseKey(w, cost[w]);
}
}
}
