private void Prim(EdgeWeightedGraph G, int s)
{
_distTo[s] = 0.0;
_pq.Insert(s, _distTo[s]);
while (!_pq.IsEmpty())
{
int v = _pq.DeleteMin();
Scan(G, v);
}
}
private IndexMinPriorityQueue<Double> _pq; //the [vertex number]|[weight] key value pairs in our minimum spanning tree
#endregion Fields
#region Constructors
public PrimMST(EdgeWeightedGraph G)
{
//initialize the various arrays and the minimum priority queue
_edgeTo = new Edge[G.V()];
_distTo = new double[G.V()];
_marked = new Boolean[G.V()];
_pq = new IndexMinPriorityQueue<Double>(G.V());
for (int v = 0; v < G.V(); v++) _distTo[v] = Double.PositiveInfinity;
for (int v = 0; v < G.V(); v++)
if (!_marked[v]) Prim(G, v);
}
private void Scan(EdgeWeightedGraph G, int v)
{
_marked[v] = true;
foreach (Edge e in G.Adj(v))
{
int w = e.Target(v);
if (_marked[w]) continue;
if (e.Weight() < _distTo[w])
{
_distTo[w] = e.Weight();
_edgeTo[w] = e;
if (_pq.Contains(w)) _pq.ChangeKey(w, _distTo[w]);
else _pq.Insert(w, _distTo[w]);
}
}
}
public void Run()
{
Console.WriteLine("Choose file:"); // Prompt
Console.WriteLine("1 - tinyEWG.txt"); // Prompt
Console.WriteLine("2 - mediumEWG.txt"); // Prompt
//Console.WriteLine("3 - mediumEWG.txt"); // Prompt
Console.WriteLine("or quit"); // Prompt
var fileNumber = Console.ReadLine();
string fileName;
switch (fileNumber)
{
case "1":
fileName = "tinyEWG.txt";
break;
case "2":
fileName = "mediumEWG.txt";
break;
//case "3":
// fileName = "largeEWG.zip";
// break;
case "quit":
return;
default:
return;
}
var @in = new In($"Files\\Graphs\\{fileName}");
var lines = @in.ReadAllLines();
var lineIterator = 0;
var v = 0;
var e = 0;
var edges = new List <EdgeW>();
foreach (var line in lines)
{
if (lineIterator == 0)
{
v = Convert.ToInt32(line);
}
if (lineIterator == 1)
{
e = Convert.ToInt32(line);
}
if (lineIterator > 1)
{
var lineSplitted = line.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
var ve = Convert.ToInt32(lineSplitted[0]);
var we = Convert.ToInt32(lineSplitted[1]);
var weight = Convert.ToDouble(lineSplitted[2], CultureInfo.InvariantCulture);
var edge = new EdgeW(ve, we, weight);
edges.Add(edge);
}
lineIterator++;
}
var edgeWeightedGraph = new EdgeWeightedGraph(v, e, edges);
Console.WriteLine(edgeWeightedGraph);
var mst = new LazyPrimMST(edgeWeightedGraph);
foreach (var edge in mst.Edges())
{
Console.WriteLine(edge);
}
Console.Write($"{$"{mst.Weight():0.00000}"}{Environment.NewLine}");
Console.ReadLine();
}
// check optimality conditions (takes time proportional to E V lg* V)
private bool check(EdgeWeightedGraph G)
{
// check total weight
double total = 0.0;
foreach (Edge e in edges())
{
total += e.Weight();
}
if (Mathf.Abs((float)(total - Weight())) > FLOATING_POINT_EPSILON)
{
throw new System.Exception("Weight of edges does not equal weight(): " + total + " vs. " + Weight() + "\n");
return(false);
}
// check that it is acyclic
UF uf = new UF(G.V());
foreach (Edge e in edges())
{
int v = e.either(), w = e.other(v);
if (uf.connected(v, w))
{
throw new System.Exception("Not a forest");
return(false);
}
uf.union(v, w);
}
// check that it is a spanning forest
foreach (Edge e in G.edges())
{
int v = e.either(), w = e.other(v);
if (!uf.connected(v, w))
{
throw new System.Exception("Not a spanning forest");
return(false);
}
}
// check that it is a minimal spanning forest (cut optimality conditions)
foreach (Edge e in edges())
{
// all edges in MST except e
uf = new UF(G.V());
foreach (Edge f in mst)
{
int x = f.either(), y = f.other(x);
if (f != e)
{
uf.union(x, y);
}
}
// check that e is min weight edge in crossing cut
foreach (Edge f in G.edges())
{
int x = f.either(), y = f.other(x);
if (!uf.connected(x, y))
{
if (f.Weight() < e.Weight())
{
throw new System.Exception("Edge " + f + " violates cut optimality conditions");
return(false);
}
}
}
}
return(true);
}
public void DrawSkelethMaze()
{
EdgeWeightedGraph MazeBasic = new EdgeWeightedGraph(25);
// int tab[25];
Random rand;
rand = new Random();
int xRand = rand.Next();
for(int i=0;i<5;i++)
{
for (int j = 0; j < 5; j++)
{
// for(int x=0;x<4;x++)
int dest = ((i + 1) * 5) + j;
if (i + 1 < 5)
{
xRand = (rand.Next() % 6) + 1;
Edge tempEdge = new Edge(i * 5 + j, dest, xRand);
MazeBasic.AddEdge(tempEdge);
}
dest = ((i - 1) * 5) + j;
if (i - 1 >= 0)
{
xRand = (rand.Next() % 6) + 1;
Edge tempEdge = new Edge(i * 5 + j, dest, xRand);
MazeBasic.AddEdge(tempEdge);
}
dest = (i * 5) + (j + 1);
if (j + 1 < 5)
{
xRand = (rand.Next() % 6) + 1;
Edge tempEdge = new Edge(i * 5 + j, dest, xRand);
MazeBasic.AddEdge(tempEdge);
}
dest = (i * 5) + (j - 1);
if (j - 1 >= 0)
{
xRand = (rand.Next() % 6) + 1;
Edge tempEdge = new Edge(i * 5 + j, dest, xRand);
MazeBasic.AddEdge(tempEdge);
}
dest =( (i + 1) * 5) + (j + 1);
if( j + 1 < 5 && i + 1 < 5)
{
xRand = (rand.Next() % 6) + 1;
Edge tempEdge = new Edge(i * 5 + j, dest, xRand);
MazeBasic.AddEdge(tempEdge);
}
}
}
PrimMST MazeBasicTree = new PrimMST(MazeBasic);
// MazeBasicTree.Edges
Queue<Edge> MazeDone = new Queue<Edge>();
int sorc,desto;
String writelienString;
foreach (Edge s in MazeBasicTree.Edges())
{
// Debug.WriteLine( s.Target. +" ");
sorc = s.Source();
desto = s.Dest();
writelienString = sorc.ToString() + " " + desto.ToString();
// Debug.WriteLine(writelienString);
}
}
public MazeStruct DrawMazeSkelethOfSize(int MazeSize,bool is_fivedirect)
{
EdgeWeightedGraph MazeBasic = new EdgeWeightedGraph(MazeSize * MazeSize);
// int tab[25];
Random rand;
rand = new Random();
int xRand = rand.Next();
for (int i = 0; i < MazeSize; i++)
{
for (int j = 0; j < MazeSize; j++)
{
// for(int x=0;x<4;x++)
int dest = ((i + 1) * MazeSize) + j;
if (i + 1 < MazeSize)
{
xRand = (rand.Next() % 6) + 1;
Edge tempEdge = new Edge(i * MazeSize + j, dest, xRand);
MazeBasic.AddEdge(tempEdge);
}
dest = ((i - 1) * MazeSize) + j;
if (i - 1 >= 0)
{
xRand = (rand.Next() % 6) + 1;
Edge tempEdge = new Edge(i * MazeSize + j, dest, xRand);
MazeBasic.AddEdge(tempEdge);
}
dest = (i * MazeSize) + (j + 1);
if (j + 1 < MazeSize)
{
xRand = (rand.Next() % 6) + 1;
Edge tempEdge = new Edge(i * MazeSize + j, dest, xRand);
MazeBasic.AddEdge(tempEdge);
}
dest = (i * MazeSize) + (j - 1);
if (j - 1 >= 0)
{
xRand = (rand.Next() % 6) + 1;
Edge tempEdge = new Edge(i * MazeSize + j, dest, xRand);
MazeBasic.AddEdge(tempEdge);
}
if (is_fivedirect)
{
dest = ((i + 1) * MazeSize) + (j + 1);
if (j + 1 < MazeSize && i + 1 < MazeSize)
{
xRand = (rand.Next() % 6) + 1;
Edge tempEdge = new Edge(i * MazeSize + j, dest, xRand);
MazeBasic.AddEdge(tempEdge);
}
}
}
}
PrimMST MazeBasicTree = new PrimMST(MazeBasic);
// MazeBasicTree.Edges
Queue<Edge> MazeDone = new Queue<Edge>();
// Queue<Edge> MazeDone = new Queue<Edge>();
// int sorc, desto;
// String writelienString;
MazeStruct MazeToReturn;
MazeToReturn = new MazeStruct(MazeSize* MazeSize);
foreach (Edge s in MazeBasicTree.Edges())
{
// Debug.WriteLine( s.Target. +" ");
MazeToReturn.setUpByEdge(s,true);
}
return MazeToReturn;
}
public void DrawMazeOfSize(int MazeSize)
{
EdgeWeightedGraph MazeBasic = new EdgeWeightedGraph(MazeSize*MazeSize);
// int tab[25];
Random rand;
rand = new Random();
int xRand = rand.Next();
for (int i = 0; i < MazeSize; i++)
{
for (int j = 0; j < MazeSize; j++)
{
// for(int x=0;x<4;x++)
int dest = ((i + 1) * MazeSize) + j;
if (i + 1 < MazeSize)
{
xRand = (rand.Next() % 6) + 1;
Edge tempEdge = new Edge(i * MazeSize + j, dest, xRand);
MazeBasic.AddEdge(tempEdge);
}
dest = ((i - 1) * MazeSize) + j;
if (i - 1 >= 0)
{
xRand = (rand.Next() % 6) + 1;
Edge tempEdge = new Edge(i * MazeSize + j, dest, xRand);
MazeBasic.AddEdge(tempEdge);
}
dest = (i * MazeSize) + (j + 1);
if (j + 1 < MazeSize)
{
xRand = (rand.Next() % 6) + 1;
Edge tempEdge = new Edge(i * MazeSize + j, dest, xRand);
MazeBasic.AddEdge(tempEdge);
}
dest = (i * MazeSize) + (j - 1);
if (j - 1 >= 0)
{
xRand = (rand.Next() % 6) + 1;
Edge tempEdge = new Edge(i * MazeSize + j, dest, xRand);
MazeBasic.AddEdge(tempEdge);
}
dest = ((i + 1) * MazeSize) + (j + 1);
if (j + 1 < MazeSize && i + 1 < MazeSize)
{
xRand = (rand.Next() % 6) + 1;
Edge tempEdge = new Edge(i * MazeSize + j, dest, xRand);
MazeBasic.AddEdge(tempEdge);
}
}
}
PrimMST MazeBasicTree = new PrimMST(MazeBasic);
// MazeBasicTree.Edges
Queue<Edge> MazeDone = new Queue<Edge>();
// MazeDone = MazeBasicTree.Edges();
//Edge TempEdge = new Edge(Center.Y,)
// int sorc, desto;
// String writelienString;
// foreach (Edge s in MazeBasicTree.Edges())
// {
// Debug.WriteLine( s.Target. +" ");
// sorc = s.Source();
// desto = s.Dest();
// writelienString = sorc.ToString() + " " + desto.ToString();
// Debug.WriteLine(writelienString);
// }
}
public void Run()
{
Console.WriteLine("Choose file:"); // Prompt
Console.WriteLine("1 - tinyEWG.txt"); // Prompt
Console.WriteLine("2 - mediumEWG.txt"); // Prompt
//Console.WriteLine("3 - mediumEWG.txt"); // Prompt
Console.WriteLine("or quit"); // Prompt
var fileNumber = Console.ReadLine();
string fileName;
int source;
switch (fileNumber)
{
case "1":
fileName = "tinyEWG.txt";
source = 6;
break;
case "2":
fileName = "mediumEWG.txt";
source = 6;
break;
//case "3":
// fileName = "largeEWG.zip";
// break;
case "quit":
return;
default:
return;
}
var @in = new In($"Files\\Graphs\\{fileName}");
var lines = @in.ReadAllLines();
var lineIterator = 0;
var v = 0;
var e = 0;
var edges = new List <EdgeW>();
foreach (var line in lines)
{
if (lineIterator == 0)
{
v = Convert.ToInt32(line);
}
if (lineIterator == 1)
{
e = Convert.ToInt32(line);
}
if (lineIterator > 1)
{
var lineSplitted = line.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
var ve = Convert.ToInt32(lineSplitted[0]);
var we = Convert.ToInt32(lineSplitted[1]);
var weight = Convert.ToDouble(lineSplitted[2], CultureInfo.InvariantCulture);
var edge = new EdgeW(ve, we, weight);
edges.Add(edge);
}
lineIterator++;
}
var edgeWeightedGraph = new EdgeWeightedGraph(v, e, edges);
Console.WriteLine(edgeWeightedGraph);
// compute shortest paths
var sp = new DijkstraUndirectedSP(edgeWeightedGraph, source);
// print shortest path
for (var t = 0; t < edgeWeightedGraph.V; t++)
{
if (sp.HasPathTo(t))
{
Console.Write($"{source} to {t} {$"{sp.DistTo(t):0.00000}"} ");
foreach (var edge in sp.PathTo(t))
{
Console.Write($"{edge} ");
}
Console.WriteLine();
}
else
{
Console.WriteLine($"{source} to {t} no path{Environment.NewLine}");
}
}
Console.ReadLine();
}