public DijkstraSP(EdgeWeightedDigraph g, int s)
{
foreach (DirectedEdge e in g.Edges())
{
if (e.Weight() < 0)
{
throw new ArgumentOutOfRangeException("graph edge must have nonegative weights");
}
}
distTo = new double[g.V];
edgeTo = new DirectedEdge[g.V];
for (int v = 0; v < g.V; v++)
{
distTo[v] = double.PositiveInfinity;
}
distTo[s] = 0;
//relax vertices in order of distance from s
pq = new IndexMinPQ <double>(g.V);
pq.Insert(s, distTo[s]);
while (!pq.IsEmpty())
{
int v = pq.DelMin();
foreach (DirectedEdge e in g.Adj(v))
{
relax(e);
}
}
}
public LazyPrimMinSpanningTree(EdgeWeightedGraph g)
{
pq = new IndexMinPQ <Edge>(g.EdgeCount);
marked = new bool[g.VertexCount];
mst = new Queue <Edge>();
Visit(g, 0);
while (!pq.IsEmpty())
{
Edge e = pq.DelMin();
int v1 = e.CurrentValue;
int v2 = e.Other(v1);
if (marked[v1] && marked[v2])
{
continue;
}
mst.Enqueue(e);
if (marked[v1])
{
Visit(g, v1);
}
if (!marked[v2])
{
Visit(g, v2);
}
}
}
private readonly IndexMinPQ<Double> _pq; // priority queue of vertices
#endregion Fields
#region Constructors
/// <summary>
/// Computes a shortest-paths tree from the source vertex <tt>s</tt> to every
/// other vertex in the edge-weighted graph <tt>G</tt>.
/// </summary>
/// <param name="g">g the edge-weighted graph</param>
/// <param name="s">s the source vertex</param>
/// <exception cref="ArgumentException">if an edge weight is negative</exception>
/// <exception cref="ArgumentException">unless 0 <= <tt>s</tt> <= <tt>V</tt> - 1</exception>
public DijkstraUndirectedSP(EdgeWeightedGraph g, int s)
{
foreach (var e in g.Edges())
{
if (e.Weight < 0)
throw new ArgumentException($"edge {e} has negative weight");
}
_distTo = new double[g.V];
_edgeTo = new EdgeW[g.V];
for (var v = 0; v < g.V; v++)
_distTo[v] = double.PositiveInfinity;
_distTo[s] = 0.0;
// relax vertices in order of distance from s
_pq = new IndexMinPQ<Double>(g.V);
_pq.Insert(s, _distTo[s]);
while (!_pq.IsEmpty())
{
var v = _pq.DelMin();
foreach (var e in g.Adj(v))
Relax(e, v);
}
// check optimality conditions
//assert check(G, s);
}
/// <summary>
/// Dijkstra algorithm (shortest path) based on graph g for start vertice s. Positive cycles are allowed in shortest path algorithm
/// </summary>
/// <param name="g">Graph for search</param>
/// <param name="s">Start vertice</param>
public static PathStats ShortestPath(GraphBase g, int s)
{
var ps = new PathStats(g.V);
for (var i = 0; i < ps.Dist.Length; i++)
{
ps.Dist[i] = int.MaxValue;
ps.Prev[i] = -1;
}
ps.Dist[s] = 0;//start vertice
var pq = new IndexMinPQ<Distance>(ps.Dist.Length);
for (int i = 0; i < ps.Dist.Length; i++)
{
pq.Insert(i, new Distance { V = i, Dist = ps.Dist[i] });
}
while (!pq.IsEmpty())
{
var v = pq.DelRoot();
foreach (var e in g.Adjacent(v))
{
if (ps.Dist[e.V2] > ps.Dist[v] + e.Weight)
{
ps.Dist[e.V2] = ps.Dist[v] + e.Weight;
ps.Prev[e.V2] = v;
pq.ChangeKey(e.V2, new Distance { V = e.V2, Dist = ps.Dist[e.V2] });
}
}
}
return ps;
}
private readonly IndexMinPQ <Double> _pq; // priority queue of vertices
/// <summary>
/// Computes a shortest-paths tree from the source vertex <tt>s</tt> to every other
/// vertex in the edge-weighted digraph <tt>G</tt>.
/// </summary>
/// <param name="g">g the edge-weighted digraph</param>
/// <param name="s">s the source vertex</param>
/// <exception cref="ArgumentException">if an edge weight is negative</exception>
/// <exception cref="ArgumentException">unless 0 <= <tt>s</tt> <= <tt>V</tt> - 1</exception>
public DijkstraSP(EdgeWeightedDigraph g, int s)
{
foreach (var e in g.Edges())
{
if (e.Weight < 0)
{
throw new ArgumentException($"edge {e} has negative weight");
}
}
_distTo = new double[g.V];
_edgeTo = new DirectedEdge[g.V];
for (var v = 0; v < g.V; v++)
{
_distTo[v] = double.PositiveInfinity;
}
_distTo[s] = 0.0;
// relax vertices in order of distance from s
_pq = new IndexMinPQ <Double>(g.V);
_pq.Insert(s, _distTo[s]);
while (!_pq.IsEmpty())
{
var v = _pq.DelMin();
foreach (var e in g.Adj(v))
{
Relax(e);
}
}
// check optimality conditions
//assert check(G, s);
}
private void prim(EdgeWeightedGraph g, int s)
{
distTo[s] = 0.0;
pq.Insert(s, distTo[s]);
while (!pq.IsEmpty())
{
int v = pq.DelMin();
scan(g, v);
}
}
/// <summary>
/// run Prim's algorithm in graph G, starting from vertex s
/// </summary>
/// <param name="g"></param>
/// <param name="s"></param>
private void Prim(EdgeWeightedGraph g, int s)
{
_distTo[s] = 0.0;
_pq.Insert(s, _distTo[s]);
while (!_pq.IsEmpty())
{
var v = _pq.DelMin();
Scan(g, v);
}
}
public DifkstraSP(EdgeWeightedDigraph g, int s)
{
_edgeTo = new DirectedEdge[g.V];
_distTo = Enumerable.Repeat(double.PositiveInfinity, g.V).ToArray();
_pq = new IndexMinPQ <double>(g.V);
_distTo[s] = 0.0;
_pq.Insert(s, 0.0);
while (!_pq.IsEmpty())
{
Relax(g, _pq.DelMin());
}
}
public DijkstraAlgorithm(EdgeWeightedDigraph digraph, int source) : base(digraph, source)
{
//pq maintain a set of vertex need to deal with.
IndexMinPQ <double> pq = new IndexMinPQ <double>(digraph.V);
pq.Insert(source, distTo[source]);
while (!pq.IsEmpty())
{
//when v pops up, the distance and path to v have been confirmed
int v = pq.DelMin();
foreach (DirectedEdge e in digraph.Adj(v))
{
Relax(pq, e);
}
}
}
public PrimMinSpanningTree(EdgeWeightedGraph g)
{
edgeTo = new Edge[g.VertexCount];
distanceTo = new double[g.VertexCount];
marked = new bool[g.VertexCount];
pq = new IndexMinPQ <double>(g.VertexCount);
for (int i = 0; i < g.VertexCount; i++)
{
distanceTo[i] = double.MaxValue;
}
distanceTo[0] = 0;
pq.Insert(0, 0);
while (!pq.IsEmpty())
{
Visit(g, pq.DeleteMin());
}
}
private readonly decimal[] _distTo; // distTo[v] = distance of shortest s->v path
#endregion Fields
#region Constructors
/**
* Computes a shortest paths tree from <tt>s</tt> to every other vertex in
* the edge-weighted digraph <tt>G</tt>.
* @param G the edge-weighted digraph
* @param s the source vertex
* @throws IllegalArgumentException if an edge weight is negative
* @throws IllegalArgumentException unless 0 ≤ <tt>s</tt> ≤ <tt>V</tt> - 1
*/
public ShortestNeuronPath(NeuronGraph G, int s)
{
_distTo = new decimal[G.V()];
edgeTo = new DirectedEdge[G.V()];
for (int v = 0; v < G.V(); v++)
_distTo[v] = decimal.MaxValue;
_distTo[s] = 0.0M;
// relax vertices in order of distance from s
pq = new IndexMinPQ<decimal>(G.V());
pq.Insert(s, _distTo[s]);
while (!pq.IsEmpty())
{
int v = pq.DelMin();
foreach (DirectedEdge e in G.adj(v))
relax(e);
}
}
void IndexMinPQTest()
{
var strArr = FileHandler.ReadFileAsStrArr("words3.txt");
strArr.Show();
var pq = new IndexMinPQ <string>(strArr.Length);
for (int i = 0; i < strArr.Length; i++)
{
pq.Insert(i, strArr[i]);
}
while (!pq.IsEmpty())
{
Console.WriteLine(pq.DelMin());
}
Console.WriteLine();
Console.ReadKey();
}
public DijkstraShortestPath(EdgeWeightedDirectedGraph graph, int start)
{
EdgeTo = new DirectedEdge[graph.VertexCount];
DistTo = new double[graph.VertexCount];
pq = new IndexMinPQ <double>(graph.VertexCount);
for (int i = 0; i < graph.VertexCount; i++)
{
DistTo[i] = double.PositiveInfinity;
DistTo[start] = 0;
pq.Insert(start, 0);
while (!pq.IsEmpty())
{
Relax(graph, pq.DeleteMin());
}
}
}
public DijkstraSP(EdgeWeightedDigraph graph, int startVertex)
{
edgeTo = new DirectedEdge[graph.Vertices];
distTo = new double[graph.Vertices];
priorityQueue = new IndexMinPQ <double>(graph.Vertices);
for (int v = 0; v < graph.Vertices; v++)
{
distTo[v] = double.MaxValue;
}
distTo[startVertex] = 0.0f;
priorityQueue.Insert(startVertex, 0.0f);
while (!priorityQueue.IsEmpty())
{
Relax(graph, priorityQueue.DelMin());
}
}
public KruskalMinSpanningTree(EdgeWeightedGraph g)
{
mst = new Queue <Edge>();
IndexMinPQ <Edge> pq = new IndexMinPQ <Edge>(g.EdgeCount);
UnionFind_1 uf = new UnionFind_1(g.VertexCount);
while (!pq.IsEmpty() && mst.Count < g.VertexCount - 1)
{
Edge e = pq.DelMin();
int v1 = e.V1;
int v2 = e.Other(v1);
if (uf.Connected(v1, v2))
{
continue;
}
uf.Union(v1, v2);
mst.Enqueue(e);
}
}
public void DifkstraSPMy(EdgeWeightedDigraph g, int s)
{
_edgeTo = new DirectedEdge[g.V];
_distTo = Enumerable.Repeat(double.PositiveInfinity, g.V).ToArray();
_distTo[s] = 0.0;
_pq = new IndexMinPQ <double>(g.V);
foreach (var e in g.Adj(s))
{
_edgeTo[e.To] = e;
_distTo[e.To] = e.Weight;
_pq.Insert(e.To, e.Weight);
}
while (!_pq.IsEmpty())
{
var i = _pq.DelMin();
foreach (var e in g.Adj(i))
{
RelaxMy(i, e);
}
}
}
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);
}
}
public PrimMst(EdgeWeightedGraph graph)
{
edgeTo = new Edge[graph.Vertices];
distTo = new double[graph.Vertices];
marked = new bool[graph.Vertices];
for (int vertex = 0; vertex < graph.Vertices; vertex++)
{
distTo[vertex] = double.MaxValue;
}
prioryQueue = new IndexMinPQ <double>(graph.Vertices);
distTo[0] = 0.0f;
prioryQueue.Insert(0, 0.0f);
while (!prioryQueue.IsEmpty())
{
Visit(graph, prioryQueue.DelMin());
}
}
//ctor inits DSs, builds shortest path tree and computes distances
//takes a built DiGraph and a source vertex
public DijkstrasShortestPath(EdgeWeightedDiGraph g, int s)
{
_pq = new IndexMinPQ <double>(g.V);
_edgeTo = new DirectedEdge[g.V];
_distTo = new double[g.V];
//load initial values
for (int i = 1; i < g.V; i++)
{
_distTo[i] = Double.PositiveInfinity;
}
_distTo[s] = 0.0;
_edgeTo[s] = null;
//loads a starting value onto PQ to start process
_pq.Insert(s, _distTo[s]);
//start business logic
//start cycle of deleting min edges and checking adj edges for 'eligability'
while (!_pq.IsEmpty())
{
var minV = _pq.DelMin();
Relax(g, minV);
}
}
