/// <summary> Finds a greedy approximation for a minimal vertex cover of a specified
/// graph. At each iteration, the algorithm picks the vertex with the
/// highest degree and adds it to the cover, until all edges are covered.
///
/// <p>
/// The algorithm works on undirected graphs, but can also work on directed
/// graphs when their edge-directions are ignored. To ignore edge
/// directions you can use {@link
/// org._3pq.jgrapht.GraphHelper#undirectedGraph(Graph)} or {@link
/// org._3pq.jgrapht.graph.AsUndirectedGraph}.
/// </p>
///
/// </summary>
/// <param name="g">the graph for which vertex cover approximation is to be found.
///
/// </param>
/// <returns> a set of vertices which is a vertex cover for the specified
/// graph.
/// </returns>
public virtual SupportClass.SetSupport findGreedyCover(UndirectedGraph g)
{
// C <-- {}
//UPGRADE_TODO: Class 'java.util.HashSet' was converted to 'SupportClass.HashSetSupport' which has a different behavior. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1073_javautilHashSet'"
SupportClass.SetSupport cover = new SupportClass.HashSetSupport();
// G' <-- G
UndirectedGraph sg = new UndirectedSubgraph(g, null, null);
// compare vertices in descending order of degree
VertexDegreeComparator comp = new VertexDegreeComparator(sg);
// while G' != {}
while (sg.edgeSet().Count > 0)
{
// v <-- vertex with maximum degree in G'
System.Object v = SupportClass.CollectionsSupport.Max(sg.vertexSet(), comp);
// C <-- C U {v}
cover.Add(v);
// remove from G' every edge incident on v, and v itself
sg.removeVertex(v);
}
return(cover);
}
/// <summary> Finds a greedy approximation for a minimal vertex cover of a specified
/// graph. At each iteration, the algorithm picks the vertex with the
/// highest degree and adds it to the cover, until all edges are covered.
///
/// <p>
/// The algorithm works on undirected graphs, but can also work on directed
/// graphs when their edge-directions are ignored. To ignore edge
/// directions you can use {@link
/// org._3pq.jgrapht.GraphHelper#undirectedGraph(Graph)} or {@link
/// org._3pq.jgrapht.graph.AsUndirectedGraph}.
/// </p>
///
/// </summary>
/// <param name="g">the graph for which vertex cover approximation is to be found.
///
/// </param>
/// <returns> a set of vertices which is a vertex cover for the specified
/// graph.
/// </returns>
public virtual SupportClass.SetSupport findGreedyCover(UndirectedGraph g)
{
// C <-- {}
//UPGRADE_TODO: Class 'java.util.HashSet' was converted to 'SupportClass.HashSetSupport' which has a different behavior. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1073_javautilHashSet'"
SupportClass.SetSupport cover = new SupportClass.HashSetSupport();
// G' <-- G
UndirectedGraph sg = new UndirectedSubgraph(g, null, null);
// compare vertices in descending order of degree
VertexDegreeComparator comp = new VertexDegreeComparator(sg);
// while G' != {}
while (sg.edgeSet().Count > 0)
{
// v <-- vertex with maximum degree in G'
System.Object v = SupportClass.CollectionsSupport.Max(sg.vertexSet(), comp);
// C <-- C U {v}
cover.Add(v);
// remove from G' every edge incident on v, and v itself
sg.removeVertex(v);
}
return cover;
}
