public void Build(Grid grid)
{
if (grid == null)
{
return;
}
int unvisitedCount = grid.UsedCells() - 1;
int switchPoint = 2 * grid.UsedCells() / 3;
Cell current = grid.RandomCell();
// AldousBorder for first third
while (unvisitedCount > switchPoint)
{
var neighbors = current.Neighbors;
Cell neighbour = neighbors.Sample();
if (neighbour.Links.IsEmpty())
{
current.Link(neighbour);
unvisitedCount--;
}
current = neighbour;
}
// and finish with Wilson
var unvisited = new CellCollection();
foreach (Cell cell in grid.GetCells())
{
if ((cell != null) &&
cell.Links.IsEmpty())
{
unvisited.Add(cell);
}
}
while (!unvisited.IsEmpty())
{
Cell cell = unvisited.Sample();
List <Cell> path = new List <Cell>();
path.Add(cell);
while (unvisited.Contains(cell))
{
cell = cell.Neighbors.Sample();
int position = path.IndexOf(cell);
if (position >= 0)
{
path.RemoveRange(position + 1, path.Count - position - 1);
}
else
{
path.Add(cell);
}
}
for (int i = 0; i < path.Count - 1; i++)
{
path[i].Link(path[i + 1]);
unvisited.Remove(path[i]);
}
}
}