public GraphColoringAlgorithm(Graph.IGraphInterface graph)
{
this.graph = graph;
countInterchangeCalls = 0;
coloredGraph = graph.GetColoredGraph();
countVertices = graph.GetRealCountVertices();
}
public void Color()
{
// Variable
int countUsedColors;
Graph.IColoredGraphInterface coloredGraph = graph.GetColoredGraph();
optimalVertexList = new List <Graph.IVertexInterface>();
coloredGraph.ResetColors();
// Try optimal color
if (TryOptimalColorInPolynomalTime(graph))
{
return;
}
// The graph can't be optimal colored => try all permutations
else
{
foreach (var vertexList in MyMath.MyMath.GeneratePermutations(graph.AllVertices()))
{
coloredGraph.GreedyColoring(vertexList.ToList());
coloredGraph.InitializeColoredGraph();
countUsedColors = coloredGraph.GetCountUsedColors();
if (optimalCountColors > countUsedColors)
{
optimalCountColors = countUsedColors;
optimalVertexList = vertexList.ToList();
}
coloredGraph.DeinitializationColoredGraph();
}
}
coloredGraph.GreedyColoring(optimalVertexList);
bool isColored = coloredGraph.InitializeColoredGraph();
if (!isColored)
{
throw new MyException.GraphColoringAlgorithmException.AlgorithmGraphIsNotColored();
}
}
/// <summary>
/// Return true if a graph has been colored in polynomal time, otherwise false
/// </summary>
/// <param name="graph">graph</param>
/// <returns>true if graph has been colored in polynomal time, otherwise false</returns>
public static bool TryOptimalColorInPolynomalTime(Graph.IGraphInterface graph)
{
bool isColored;
IGraphColoringAlgorithmInterface algorithm;
List <Graph.IVertexInterface> optimalVertexList;
Graph.IColoredGraphInterface coloredGraph = graph.GetColoredGraph();
coloredGraph.ResetColors();
// If the graph is chordal => use PEO for coloring
if (graph.GetGraphProperty().GetIsChordal())
{
optimalVertexList = graph.GetGraphProperty().GetPerfectEliminationOrdering();
coloredGraph.GreedyColoring(optimalVertexList);
isColored = coloredGraph.InitializeColoredGraph();
if (!isColored)
{
throw new MyException.GraphColoringAlgorithmException.AlgorithmGraphIsNotColored();
}
return(true);
}
switch (graph.GetGraphProperty().GetGraphClass())
{
case Graph.GraphClass.GraphClass.GraphClassEnum.bipartiteGraph:
Tuple <List <Graph.IVertexInterface>, List <Graph.IVertexInterface> > partites = graph.GetGraphProperty().GetPartites();
coloredGraph.GreedyColoring(partites.Item1.Concat(partites.Item2).ToList());
isColored = coloredGraph.InitializeColoredGraph();
if (!isColored)
{
throw new MyException.GraphColoringAlgorithmException.AlgorithmGraphIsNotColored();
}
return(true);
case Graph.GraphClass.GraphClass.GraphClassEnum.completeBipartiteGraph:
algorithm = new SequenceAlgorithm.SmallestLastSequence.SmallestLastSequence(graph);
algorithm.Color();
return(true);
case Graph.GraphClass.GraphClass.GraphClassEnum.completeGraph:
coloredGraph.GreedyColoring(graph.AllVertices());
isColored = coloredGraph.InitializeColoredGraph();
if (!isColored)
{
throw new MyException.GraphColoringAlgorithmException.AlgorithmGraphIsNotColored();
}
return(true);
case Graph.GraphClass.GraphClass.GraphClassEnum.cycleGraph:
case Graph.GraphClass.GraphClass.GraphClassEnum.treeGraph:
algorithm = new SequenceAlgorithm.ConnectedSequential.ConnectedSequential(graph);
algorithm.Color();
return(true);
}
return(false);
}