/// <summary>
/// trouve la partie correspondant a l'élement i passé en paramétres
/// </summary>
/// <param name="Nodes">Noeud courant</param>
/// <param name="i">élement i</param>
/// <returns>valeur du noeud parent</returns>
public int Find(KruskalNode[] Nodes, int i)
{
// find root and make root as parent of i (path compression)
if (Nodes[i].Parent != i)
{
Nodes[i].Parent = Find(Nodes, Nodes[i].Parent);
}
return Nodes[i].Parent;
}
/// <summary>
/// Kruskal algorythm
/// </summary>
public List <KruskalEdge> KruskalMST()
{
//Stocke le résultat de l'algorithme
List <KruskalEdge> result = new List <KruskalEdge>();
//Réorganise le tableau dans l'ordre de leur poids du plus petit au plus grand
Array.Sort(Edges);
// Allocate memory for creating V Nodes
KruskalNode[] subsets = new KruskalNode[NumberofNodes];
for (int i = 0; i < NumberofNodes; ++i)
{
subsets[i] = new KruskalNode();
subsets[i].Parent = i;
subsets[i].Value = 0;
}
int j = 0; // Index used to pick next edge
int e = 0; // An index variable, used for result[]
// Number of edges to be taken is equal to V-1
while (e < NumberofNodes - 1)
{
// Step 2: Pick the smallest edge. And increment the index
// for next iteration
KruskalEdge next_edge;
next_edge = Edges[j++];
int x = Find(subsets, next_edge.From);
int y = Find(subsets, next_edge.To);
// If including this edge does't cause cycle, include it
// in result and increment the index of result for next edge
if (x != y)
{
result.Add(new KruskalEdge());
result[e++] = next_edge;
Union(subsets, x, y);
}
// Else discard the next_edge
}
return(result);
}
/// <summary>
/// Kruskal algorythm
/// </summary>
public List<KruskalEdge> KruskalMST()
{
//Stocke le résultat de l'algorithme
List<KruskalEdge> result = new List<KruskalEdge>();
//Réorganise le tableau dans l'ordre de leur poids du plus petit au plus grand
Array.Sort(Edges);
// Allocate memory for creating V Nodes
KruskalNode[] subsets = new KruskalNode[NumberofNodes];
for (int i = 0; i < NumberofNodes; ++i)
{
subsets[i] = new KruskalNode();
subsets[i].Parent = i;
subsets[i].Value = 0;
}
int j = 0; // Index used to pick next edge
int e = 0; // An index variable, used for result[]
// Number of edges to be taken is equal to V-1
while (e < NumberofNodes - 1)
{
// Step 2: Pick the smallest edge. And increment the index
// for next iteration
KruskalEdge next_edge = new KruskalEdge();
next_edge = Edges[j++];
int x = Find(subsets, next_edge.From);
int y = Find(subsets, next_edge.To);
// If including this edge does't cause cycle, include it
// in result and increment the index of result for next edge
if (x != y)
{
result.Add(new KruskalEdge());
result[e++] = next_edge;
Union(subsets, x, y);
}
// Else discard the next_edge
}
return result;
}
/// <summary>
/// Fais l'union entre 2 noeuds en fonction de leur valeur
/// </summary>
/// <param name="nodes"></param>
/// <param name="x"></param>
/// <param name="y"></param>
public void Union(KruskalNode[] nodes, int x, int y)
{
int xroot = Find(nodes, x);
int yroot = Find(nodes, y);
// Attach smaller rank tree under root of high rank tree
// (Union by Rank)
if (nodes[xroot].Value < nodes[yroot].Value)
{
nodes[xroot].Parent = yroot;
}
else if (nodes[xroot].Value > nodes[yroot].Value)
{
nodes[yroot].Parent = xroot;
}
else // If ranks are same, then make one as root and increment its rank by one
{
nodes[yroot].Parent = xroot;
nodes[xroot].Value++;
}
}