/// <summary> Finds a 2-approximation for a minimal vertex cover of the specified
/// graph. The algorithm promises a cover that is at most double the size
/// of a minimal cover. The algorithm takes O(|E|) time.
///
/// <p>
/// For more details see Jenny Walter, CMPU-240: Lecture notes for Language
/// Theory and Computation, Fall 2002, Vassar College, <a
/// href="http://www.cs.vassar.edu/~walter/cs241index/lectures/PDF/approx.pdf">
///
/// http://www.cs.vassar.edu/~walter/cs241index/lectures/PDF/approx.pdf</a>.
/// </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 find2ApproximationCover(Graph 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'=(V',E') <-- G(V,E)
Subgraph sg = new Subgraph(g, null, null);
// while E' is non-empty
while (sg.edgeSet().Count > 0)
{
// let (u,v) be an arbitrary edge of E'
//UPGRADE_TODO: Method 'java.util.Iterator.next' was converted to 'System.Collections.IEnumerator.Current' which has a different behavior. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1073_javautilIteratornext'"
Edge e = (Edge)sg.edgeSet().GetEnumerator().Current;
// C <-- C U {u,v}
System.Object u = e.Source;
System.Object v = e.Target;
cover.Add(u);
cover.Add(v);
// remove from E' every edge incident on either u or v
sg.removeVertex(u);
sg.removeVertex(v);
}
return(cover); // return C
}
/// <summary> Finds a 2-approximation for a minimal vertex cover of the specified
/// graph. The algorithm promises a cover that is at most double the size
/// of a minimal cover. The algorithm takes O(|E|) time.
///
/// <p>
/// For more details see Jenny Walter, CMPU-240: Lecture notes for Language
/// Theory and Computation, Fall 2002, Vassar College, <a
/// href="http://www.cs.vassar.edu/~walter/cs241index/lectures/PDF/approx.pdf">
///
/// http://www.cs.vassar.edu/~walter/cs241index/lectures/PDF/approx.pdf</a>.
/// </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 find2ApproximationCover(Graph 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'=(V',E') <-- G(V,E)
Subgraph sg = new Subgraph(g, null, null);
// while E' is non-empty
while (sg.edgeSet().Count > 0)
{
// let (u,v) be an arbitrary edge of E'
//UPGRADE_TODO: Method 'java.util.Iterator.next' was converted to 'System.Collections.IEnumerator.Current' which has a different behavior. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1073_javautilIteratornext'"
Edge e = (Edge) sg.edgeSet().GetEnumerator().Current;
// C <-- C U {u,v}
System.Object u = e.Source;
System.Object v = e.Target;
cover.Add(u);
cover.Add(v);
// remove from E' every edge incident on either u or v
sg.removeVertex(u);
sg.removeVertex(v);
}
return cover; // return C
}
