/// <summary>
/// Computes the number of Eulerian trails in the graph.
/// </summary>
/// <param name="graph">Graph to visit.</param>
/// <returns>Number of Eulerian trails.</returns>
public static int ComputeEulerianPathCount(
IVertexAndEdgeListGraph <TVertex, TEdge> graph)
{
if (graph is null)
{
throw new ArgumentNullException(nameof(graph));
}
if (graph.EdgeCount < graph.VertexCount)
{
return(0);
}
int odd = graph.OddVertices().Count();
if (odd == 0)
{
return(1);
}
if (odd % 2 != 0)
{
return(0);
}
return(odd / 2);
}
