EdgeBasedTwoApproxVCImpl (JGraphT : a free Java graph library)

java.lang.Object
- org.jgrapht.alg.vertexcover.EdgeBasedTwoApproxVCImpl<V,E>

Type Parameters:

V - the graph vertex type

E - the graph edge type

All Implemented Interfaces:

VertexCoverAlgorithm<V>
```
public class EdgeBasedTwoApproxVCImpl<V,E>
extends Object
implements VertexCoverAlgorithm<V>
```
Finds a 2-approximation for a minimum vertex cover A vertex cover is a set of vertices that touches all the edges in the graph. The graph's vertex set is a trivial cover. However, a minimal vertex set (or at least an approximation for it) is usually desired. Finding a true minimal vertex cover is an NP-Complete problem. For more on the vertex cover problem, see http://mathworld.wolfram.com/VertexCover.html Note: this class supports pseudo-graphs

Author:

Linda Buisman

Nested Class Summary
- Nested classes/interfaces inherited from interface org.jgrapht.alg.interfaces.VertexCoverAlgorithm
  VertexCoverAlgorithm.VertexCover<V>, VertexCoverAlgorithm.VertexCoverImpl<V>

Constructor Summary

Constructors
Constructor Description

EdgeBasedTwoApproxVCImpl(Graph<V,E> graph)
Constructs a new EdgeBasedTwoApproxVCImpl instance

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`VertexCoverAlgorithm.VertexCover<V>`	`getVertexCover()`	Finds a 2-approximation for a minimal vertex cover of the specified graph.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - EdgeBasedTwoApproxVCImpl
```
public EdgeBasedTwoApproxVCImpl(Graph<V,E> graph)
```
    Constructs a new EdgeBasedTwoApproxVCImpl instance
    
    Parameters:
    
    graph - input graph
- Method Detail
  - getVertexCover
```
public VertexCoverAlgorithm.VertexCover<V> getVertexCover()
```
    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. Note: this class supports pseudo-graphs Runtime: O(|E|) Albeit the fact that this is a 2-approximation algorithm for vertex cover, its results are often of lower quality than the results produced by BarYehudaEvenTwoApproxVCImpl or ClarksonTwoApproxVCImpl.
    For more details see Jenny Walter, CMPU-240: Lecture notes for Language Theory and Computation, Fall 2002, Vassar College, http://www.cs.vassar.edu/~walter/cs241index/lectures/PDF/approx.pdf.
    
    Specified by:
    
    getVertexCover in interface VertexCoverAlgorithm<V>
    
    Returns:
    
    a set of vertices which is a vertex cover for the specified graph.