/// <summary>
/// Saves given <paramref name="coloring"/> into <paramref name="writer"/> in TGF-like text representation.
/// The color of each vertex is saved as a second number, after vertex id. So a vertex with id=1, label=sth
/// colored with number 132 will be saved in TGF vertex list as "1 132 sth".
/// </summary>
/// <param name="writer">Writer to save coloring to.</param>
/// <param name="graph">Coloring to be saved.</param>
public static void WriteColoringAsTgf(this TextWriter writer, GraphColoring coloring)
{
var graph = coloring.Graph;
foreach (var vertex in graph.Vertices)
{
writer.WriteLine($"{vertex.Id} {coloring[vertex]} {vertex.Label}");
}
writer.WriteLine("#");
foreach (var edge in graph.Edges)
{
writer.WriteLine(edge.ToString());
}
}
/// <summary>
/// Calculates count of unique colors used in <paramref name="coloring"/>.
/// </summary>
/// <param name="coloring">Coloring to count colors in.</param>
/// <returns>Count of unique colors.</returns>
public static int ColorsUsed(this GraphColoring coloring)
{
return(coloring.VertexColors.Values.Distinct().Count());
}