public int CountConflictsAndUpdateCandidates(Dictionary <int, Color> solution, HashSet <int> candidates = null)
{
var conflicts = 0;
//Since it's undirect graph go just over upper triangle of adjacency matrix
for (int i = 0; i < graph.GetNumberOfVertices(); i++)
{
for (int j = i + 1; j < graph.GetNumberOfVertices(); j++)
{
if (!IsBadEdge(i, j, solution))
{
continue;
}
if (candidates != null)
{
candidates.Add(i);
candidates.Add(j);
}
conflicts++;
}
}
return(conflicts);
}
public UndirectedGraph Crossover(UndirectedGraph parent1, UndirectedGraph parent2)
{
var random = new Random();
var crosspoint = random.Next(0, parent1.GetNumberOfVertices() - 1);
var graph = new UndirectedGraph(parent1.GetNumberOfVertices());
for (int i = 0; i < parent1.GetNumberOfVertices(); i++)
{
if (i < crosspoint)
{
graph.SetColor(i, parent1.GetColor(i).Value);
}
else
{
graph.SetColor(i, parent2.GetColor(i).Value);
}
}
return(graph);
}
public bool ContainsBadEdge(UndirectedGraph graph)
{
for (int i = 0; i < graph.GetNumberOfVertices(); i++)
{
var color = graph.GetColor(i);
if (graph.GetNeighbourColors(i).Contains(color))
{
return(true);
}
}
return(false);
}
public int Fitness(UndirectedGraph graph)
{
var usedColors = new List <Color>();
for (int i = 0; i < graph.GetNumberOfVertices(); i++)
{
if (!usedColors.Contains((Color)graph.GetColor(i)))
{
usedColors.Add((Color)graph.GetColor(i));
}
}
return(usedColors.Count);
}
public Dictionary <int, Color> GenerateGreedySolutionDict(UndirectedGraph graph)
{
var greedy = new GraphColoringGreedy(graph);
greedy.Color();
var res = new Dictionary <int, Color>();
for (int i = 0; i < graph.GetNumberOfVertices(); i++)
{
res.Add(i, (Color)graph.GetColor(i));
}
return(res);
}
public UndirectedGraph GenerateRandomInstance()
{
var random = new Random();
var graph = new UndirectedGraph(100);
var numberOfVertices = graph.GetNumberOfVertices();
var maxEdges = numberOfVertices * (numberOfVertices - 1) / 2;
for (int i = 0; i < 5000; i++)
{
graph.AddEdge(random.Next(1, numberOfVertices), random.Next(1, numberOfVertices));
}
return(graph);
}
public void SaveToFile(UndirectedGraph graph, string filePath)
{
if (string.IsNullOrWhiteSpace(filePath))
{
filePath = "results.txt";
}
using (StreamWriter sw = new StreamWriter(filePath))
{
sw.WriteLine(graph.GetNumberOfVertices());
foreach (var item in graph.GetEdgesList())
{
sw.WriteLine($"{item.Item1} {item.Item2}");
}
}
}
public void Mutate(UndirectedGraph graph)
{
var random = new Random();
for (int i = 0; i < graph.GetNumberOfVertices(); i++)
{
var neightboursColors = graph.GetNeighbourColors(i);
var color = graph.GetColor(i);
if (neightboursColors.Contains(color))
{
var colors = Enum.GetValues(typeof(Color)).Cast <Color>().ToList();
foreach (var neighbourColor in neightboursColors)
{
colors.Remove((Color)neighbourColor);
}
colors.OrderBy(x => random.Next(0, colors.Count - 1));
graph.SetColor(i, colors.FirstOrDefault());
}
}
}
public int Color()
{
var numberOfVertices = _graph.GetNumberOfVertices();
var usedColors = new List <Color>();
var result = 0;
for (int i = 0; i < numberOfVertices; i++)
{
var usedNeighbourColors = _graph.GetNeighbourColors(i);
var firstAvailableColor = GetFirstAvailableColor(usedNeighbourColors);
_graph.SetColor(i, firstAvailableColor);
if (!usedColors.Contains(firstAvailableColor))
{
usedColors.Add(firstAvailableColor);
result++;
}
}
return(result);
}
public void ColorRandomly(UndirectedGraph graph)
{
var random = new Random();
for (int i = 0; i < graph.GetNumberOfVertices(); i++)
{
var neightboursColors = graph.GetNeighbourColors(i);
while (true)
{
var colors = Enum.GetValues(typeof(Color)).Cast <Color>().ToList();
foreach (var neighbourColor in neightboursColors)
{
colors.Remove((Color)neighbourColor);
}
if (colors.Count == 0)
{
throw new Exception("Not enough colors");
}
colors.OrderBy(x => random.Next(0, colors.Count - 1));
graph.SetColor(i, colors.FirstOrDefault());
break;
}
}
}