public void Initialize()
{
_target = new IndexMinPQ<Distance>(4);
_target.Insert(2, new Distance { V = 2, Dist = 1 });
_target.Insert(1, new Distance { V = 1, Dist = 2 });
_target.Insert(0, new Distance { V = 0, Dist = 3 });
}
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);
}
}
/// <summary>
/// Demo test the <c>IndexMinPQ</c> data type.</summary>
/// <param name="args">Place holder for user arguments</param>
///
public static void MainTest(string[] args)
{
// insert a bunch of strings
string[] strings =
{
"it",
"was",
"the",
"best",
"of",
"times",
"it",
"was",
"the",
"worst"
};
IndexMinPQ <string> pq = new IndexMinPQ <string>(strings.Length);
for (int i = 0; i < strings.Length; i++)
{
pq.Insert(i, strings[i]);
}
// delete and print each key
while (!pq.IsEmpty)
{
int i = pq.DelMin();
Console.WriteLine(i + " " + strings[i]);
}
Console.WriteLine();
// reinsert the same strings
for (int i = 0; i < strings.Length; i++)
{
pq.Insert(i, strings[i]);
}
// print each key using the iterator
foreach (int i in pq)
{
Console.WriteLine(i + " " + strings[i]);
}
while (!pq.IsEmpty)
{
Console.WriteLine("Min k={0} at {1}", pq.MinKey, pq.MinIndex);
Console.WriteLine("Removed {0}", pq.DelMin());
}
}
private void Visit(EdgeWeightedGraph graph, int vertex)
{
marked[vertex] = true;
foreach (var edge in graph.Adj(vertex))
{
int otherVertex = edge.Other(vertex);
if (marked[otherVertex])
{
continue;
}
if (!(edge.Weight < distTo[otherVertex]))
{
continue;
}
edgeTo[otherVertex] = edge;
distTo[otherVertex] = edge.Weight;
if (prioryQueue.Contains(otherVertex))
{
prioryQueue.ChangeKey(otherVertex, distTo[otherVertex]);
}
else
{
prioryQueue.Insert(otherVertex, distTo[otherVertex]);
}
}
}
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);
}
}
}
/// <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;
}
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);
}
}
}
private void Visit(IEdgeWeightGraph g, int v)
{
marked[v] = true;
foreach (var e in g.Adj(v))
{
int w = e.Other(v);
if (marked[w])
{
continue;
}
if (e.Weight < distTo[w]) //更新最佳的边
{
edgeTo[w] = e;
distTo[w] = e.Weight;
if (pq.Contains(w))
{
pq.ChangeKey(w, distTo[w]);
}
else
{
pq.Insert(w, distTo[w]);
}
}
}
}
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($"edge {e} has negative weight");
}
_distTo = new double[g.V];
_edgeTo = new EdgeW[g.V];
for (var v = 0; v < g.V; v++)
_distTo[v] = double.PositiveInfinity;
_distTo[s] = 0.0;
// relax vertices in order of distance from s
_pq = new IndexMinPQ<Double>(g.V);
_pq.Insert(s, _distTo[s]);
while (!_pq.IsEmpty())
{
var v = _pq.DelMin();
foreach (var e in g.Adj(v))
Relax(e, v);
}
// check optimality conditions
//assert check(G, s);
}
public void Visit(EdgeWeightedGraph g, int v)
{
marked[v] = true;
foreach (var edge in g.Adj(v))
{
int v2 = edge.Other(v);
if (marked[v2])
{
continue;
}
if (edge.Weight < distanceTo[v2])
{
edgeTo[v2] = edge;
distanceTo[v2] = edge.Weight;
if (pq.Contains(v2))
{
pq.Change(v2, distanceTo[v2]);
}
else
{
pq.Insert(v2, distanceTo[v2]);
}
}
}
}
private readonly IndexMinPQ <Double> _pq; // priority queue of vertices
/// <summary>
/// Computes a shortest-paths tree from the source vertex <tt>s</tt> to every other
/// vertex in the edge-weighted digraph <tt>G</tt>.
/// </summary>
/// <param name="g">g the edge-weighted digraph</param>
/// <param name="s">s the source vertex</param>
/// <exception cref="ArgumentException">if an edge weight is negative</exception>
/// <exception cref="ArgumentException">unless 0 <= <tt>s</tt> <= <tt>V</tt> - 1</exception>
public DijkstraSP(EdgeWeightedDigraph g, int s)
{
foreach (var e in g.Edges())
{
if (e.Weight < 0)
{
throw new ArgumentException($"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);
}
public DijkstraSP(IEdgeWeightedDIgraph G, int s) : base(G, s)
{
pq = new IndexMinPQ <double>(G.V);
pq.Insert(s, 0.0);
while (!pq.IsEmpty)
{
Relax(G, pq.DeleteMin());
}
}
// add all items to copy of heap
// takes linear time since already in heap order so no keys move
public HeapIEnumerator(IndexMinPQ <Key> minpq)
{
innerPQ = new IndexMinPQ <Key>(minpq.Count);
for (int i = 1; i <= minpq.N; i++)
{
innerPQ.Insert(minpq.pq[i], minpq.keys[minpq.pq[i]]);
}
copy = innerPQ;
}
private void Relax(EdgeWeightedDigraph g, int v)
{
foreach (var e in g.Adj(v))
{
int w = e.To;
if (_distTo[v] + e.Weight < _distTo[w])
{
_edgeTo[w] = e;
_distTo[w] = _distTo[v] + e.Weight;
if (_pq.Contains(e.To))
{
_pq.Change(e.To, _distTo[w]);
}
else
{
_pq.Insert(e.To, _distTo[w]);
}
}
}
}
public void Visit(EdgeWeightedGraph g, int v)
{
marked[v] = true;
foreach (var edge in g.Adj(v))
{
if (!marked[edge.Other(v)])
{
Edge temp = new Edge(edge.V1, edge.V2, edge.CurrentValue);
pq.Insert(0, temp);
}
}
}
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 void IndexMinPQ_Enqueue()
{
var q = new IndexMinPQ<int>(items.Length);
var minItem = int.MaxValue;
for (int i = 0; i < items.Length; i++)
{
// After adding each item, the min item should be on top
q.Insert(i, items[i]);
minItem = Math.Min(items[i], minItem);
Assert.AreEqual(q.MinKey(), minItem);
}
}
public void Run()
{
Console.WriteLine("Choose file:"); // Prompt
Console.WriteLine("1 - tinyPQ.txt"); // Prompt
Console.WriteLine("or quit"); // Prompt
var fileNumber = Console.ReadLine();
var fieName = string.Empty;
switch (fileNumber)
{
case "1":
fieName = "tinyIndexPQ.txt";
break;
case "quit":
return;
default:
return;
}
var @in = new In($"Files\\Sorting\\{fieName}");
var words = @in.ReadAllStrings();
//var list = words.Select(word => new StringComparable(word)).ToList();
//var listComparable = list.Cast<IComparable>().ToList();
//var arrayComparable = list.Cast<IComparable>().ToArray();
var listStrings = words.ToList();
var pq = new IndexMinPQ <string>(listStrings.Count);
//Fill Priority Queue
for (var i = 0; i < listStrings.Count; i++)
{
pq.Insert(i, listStrings[i]);
}
// print results
foreach (var item in pq)
{
Console.WriteLine(pq.KeyOf(item));
}
Console.ReadLine();
}
public void IndexMinPQTest1()
{
const int MaxSize = 8;
const double MinValue = 3.9;
const double MaxValue = MinValue * MaxSize + 32;
int index;
// MinValue index == 3, MaxValue index == 4
double[] items = { MinValue * 2, MinValue * 3, MinValue * 4, MinValue, MaxValue, MinValue * 5, MinValue * 6, MinValue * 7 };
StdRandom.Seed = 101;
IndexMinPQ <double> pq = new IndexMinPQ <double>(MaxSize);
index = StdRandom.Uniform(items.Length);
Assert.IsFalse(pq.Contains(index));
Assert.IsTrue(pq.IsEmpty);
Assert.AreEqual(0, pq.Count);
try
{
index = pq.DelMin();
Assert.Fail("Failed to catch exception");
}
catch (InvalidOperationException) { }
for (int i = 0; i < items.Length; i++)
{
pq.Insert(i, items[i]);
}
Assert.AreEqual(items.Length, pq.Count);
Assert.AreEqual(MinValue, pq.MinKey);
Assert.AreEqual(3, pq.MinIndex);
Assert.AreEqual(MaxValue, pq.KeyOf(4));
index = StdRandom.Uniform(items.Length);
Assert.AreEqual(items[index], pq.KeyOf(index));
pq.ChangeKey(1, pq.MinKey * 0.9); // make it the smallest item
Assert.AreEqual(1, pq.MinIndex);
pq.DecreaseKey(3, pq.MinKey * 0.87);
Assert.AreEqual(3, pq.MinIndex);
pq.Delete(3);
Assert.AreNotEqual(3, pq.MinIndex);
Assert.AreEqual(1, 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);
}
}
}
private IndexMinPQ <double> pq; //有效的横切边
public PrimeMST(IEdgeWeightGraph G)
{
edgeTo = new Edge[G.V];
distTo = new double[G.V];
marked = new bool[G.V];
for (int v = 0; v < G.V; v++)
{
distTo[v] = Double.PositiveInfinity;
}
pq = new IndexMinPQ <double>(G.V);
distTo[0] = 0.0;
pq.Insert(0, 0.0); //顶点0权重初始化
while (!pq.IsEmpty)
{
Visit(G, pq.DeleteMin());
}
}
/// <summary>
/// relax edge e and update pq if changed
/// </summary>
/// <param name="e"></param>
/// <param name="v"></param>
private void Relax(EdgeW e, int v)
{
var w = e.Other(v);
if (_distTo[w] > _distTo[v] + e.Weight)
{
_distTo[w] = _distTo[v] + e.Weight;
_edgeTo[w] = e;
if (_pq.Contains(w))
{
_pq.DecreaseKey(w, _distTo[w]);
}
else
{
_pq.Insert(w, _distTo[w]);
}
}
}
public void IndexMinPQ_Dequeue()
{
var q = new IndexMinPQ<int>(items.Length);
for (int i = 0; i < items.Length; i++)
{
q.Insert(i, items[i]);
}
var sortedItems = new List<int>(items);
sortedItems.Sort();
foreach (var item in sortedItems)
{
// The top of the queue returns the items in sorted order
var minIndex = q.DelMin();
Assert.AreEqual(items[minIndex], item);
}
}
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);
}
}
/// <summary>
/// relax edge e and update pq if changed
/// </summary>
/// <param name="e"></param>
private void Relax(DirectedEdge e)
{
int v = e.From(), w = e.To();
if (_distTo[w] > _distTo[v] + e.Weight)
{
_distTo[w] = _distTo[v] + e.Weight;
_edgeTo[w] = e;
if (_pq.Contains(w))
{
_pq.DecreaseKey(w, _distTo[w]);
}
else
{
_pq.Insert(w, _distTo[w]);
}
}
}
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 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());
}
}
void Relax(EdgeWeightedDirectedGraph graph, int vertex)
{
foreach (var edge in graph.Adj(vertex))
{
int v2 = edge.End;
if (DistTo[v2] > DistTo[vertex] + edge.Weight)
{
DistTo[v2] = DistTo[vertex] + edge.Weight;
EdgeTo[v2] = edge;
if (pq.Contains(v2))
{
pq.Change(v2, DistTo[v2]);
}
pq.Insert(v2, DistTo[v2]);
}
}
}
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());
}
}
}
private void Visit(WeightedGraph G, int v)
{
marked[v] = true;
foreach (var e in G.adj(v))
{
int w = e.other(v);
if (!marked[w])
{
if (!pq.Contains(w))
{
pq.Insert(w, e);
}
else
{
pq.DecreaseKey(w, e);
}
}
}
}
/// <summary>
/// relax edge e and update pq if changed
/// relax defined as follows: to relax an edge v-->w means to test whether the best known way from s to w is to go from s to v, then take the edge from v to w.If so, update our data structures to indicate that
/// </summary>
/// <param name="e"></param>
private void relax(DirectedEdge e)
{
int v = e.From();
int w = e.To();
if (distTo[w] > distTo[v] + e.Weight())
{
distTo[w] = distTo[v] + e.Weight();
edgeTo[w] = e;
if (pq.Contains(w))
{
pq.DecreaseKey(w, distTo[w]);
}
else
{
pq.Insert(w, distTo[w]);
}
}
}
private void Relax(WeightedDiGraph G, Edge 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]);
}
}
}
protected void Relax(IndexMinPQ <double> pq, DirectedEdge e)
{
int v = e.From;
int w = e.To;
if (distTo[w] > distTo[v] + e.Weight)
{
distTo[w] = distTo[v] + e.Weight;
edgeTo[w] = e;
if (pq.Contains(w))
{
pq.DecreaseKey(w, distTo[w]);
}
else
{
//this will never used
pq.Insert(w, distTo[w]);
}
}
}
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());
}
}
private void Relax(IEdgeWeightedDIgraph g, int v)
{
foreach (var e in g.Adj(v))
{
int w = e.To;
if (distTo[w] > distTo[v] + e.Weight)
{
distTo[w] = distTo[v] + e.Weight;
edgeTo[w] = e;
if (pq.Contains(w))
{
pq.ChangeKey(w, distTo[w]);
}
else
{
pq.Insert(w, distTo[w]);
}
}
}
}