Package org.jgrapht.alg.vertexcover
Class BarYehudaEvenTwoApproxVCImpl<V,E>
- java.lang.Object
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- org.jgrapht.alg.vertexcover.BarYehudaEvenTwoApproxVCImpl<V,E>
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- Type Parameters:
V
- the graph vertex typeE
- the graph edge type
- All Implemented Interfaces:
VertexCoverAlgorithm<V>
public class BarYehudaEvenTwoApproxVCImpl<V,E> extends java.lang.Object implements VertexCoverAlgorithm<V>
Implementation of the 2-opt algorithm for a minimum weighted vertex cover by R. Bar-Yehuda and S. Even. A linear time approximation algorithm for the weighted vertex cover problem. J. of Algorithms 2:198-203, 1981. The solution is guaranteed to be within $2$ times the optimum solution. An easier-to-read version of this algorithm can be found here: https://www.cs.umd.edu/class/spring2011/cmsc651/vc.pdf Note: this class supports pseudo-graphs Runtime: $O(|E|)$ This is a fast algorithm, guaranteed to give a $2$-approximation. A solution of higher quality (same approximation ratio) at the expensive of a higher runtime can be obtained usingBarYehudaEvenTwoApproxVCImpl
. TODO: Remove the UndirectedSubgraph dependency! Querying vertex degrees on these graphs is actually slow! This does affect the runtime complexity. Better would be to just work on a clone of the original graph!- Author:
- Joris Kinable
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Nested Class Summary
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Nested classes/interfaces inherited from interface org.jgrapht.alg.interfaces.VertexCoverAlgorithm
VertexCoverAlgorithm.VertexCover<V>, VertexCoverAlgorithm.VertexCoverImpl<V>
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Constructor Summary
Constructors Constructor Description BarYehudaEvenTwoApproxVCImpl(Graph<V,E> graph)
Constructs a new BarYehudaEvenTwoApproxVCImpl instance where all vertices have uniform weights.BarYehudaEvenTwoApproxVCImpl(Graph<V,E> graph, java.util.Map<V,java.lang.Double> vertexWeightMap)
Constructs a new BarYehudaEvenTwoApproxVCImpl instance
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description VertexCoverAlgorithm.VertexCover<V>
getVertexCover()
Computes a vertex cover.
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Method Detail
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getVertexCover
public VertexCoverAlgorithm.VertexCover<V> getVertexCover()
Description copied from interface:VertexCoverAlgorithm
Computes a vertex cover.- Specified by:
getVertexCover
in interfaceVertexCoverAlgorithm<V>
- Returns:
- a vertex cover
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