public void Ellers()
{
AllWalls();
ChangeCells(Out, In);
int x0, x1, y0, y1;
GetBounds(out x0, out x1, out y0, out y1, In);
int rowLen = 1 + (x1 - x0) / 2;
ArrayOfSets cur = new ArrayOfSets(rowLen);
for (int y = y0; y <= y1 - 2; y += 2)
{
// Join some adjacent cells in the row at random
for (int i = 1; i < rowLen; ++i)
{
int x = x0 + i * 2;
if (cur[i - 1] != cur[i] && Rnd(2) != 0)
{
SetWall(new Pt(x, y), new Pt(x - 2, y), false);
cur.JoinAt(i, i - 1);
}
}
// Make vertical connections
ArrayOfSets next = new ArrayOfSets(rowLen);
int[] sets = cur.SetIDs.ToArray();
for (int i = 0; i < sets.Length; ++i)
{
int[] posns = cur.PositionsOf(sets[i]);
int conn = Math.Max(1, posns.Length / 2);
while (conn > 0)
{
int r = RandomOf(posns);
int x2 = x0 + 2 * r;
if (GetWall(new Pt(x2, y), new Pt(x2, y + 2)))
{
SetWall(new Pt(x2, y), new Pt(x2, y + 2), false);
next[r] = cur[r];
--conn;
}
}
}
cur = next;
}
// Join sets on final row
for (int i = 1; i < rowLen; ++i)
{
if (cur[i - 1] != cur[i])
{
int x = x0 + 2 * i;
SetWall(new Pt(x - 2, y1), new Pt(x, y1), false);
cur.JoinAt(i, i - 1);
}
}
}
public void Kruskals()
{
AllWalls();
ChangeCells(Out, In);
// Build a list of walls
List <Pt> wallsFrom = new List <Pt>();
List <Pt> wallsTo = new List <Pt>();
foreach (Pt from in Locs)
{
foreach (Pt to in Select(Neighbours(from), In))
{
if (from.CompareTo(to) < 0)
{
wallsFrom.Add(from);
wallsTo.Add(to);
}
}
}
// Map points to entries in an array of sets
Dictionary <Pt, int> dict = new Dictionary <Pt, int>();
int ind = 0;
foreach (Pt pt in Locs)
{
dict[pt] = ind++;
}
ArrayOfSets arr = new ArrayOfSets(ind);
// For each wall, in random order
while (wallsFrom.Count > 0)
{
int i = Rnd(wallsFrom.Count);
Pt from = wallsFrom[i];
Pt to = wallsTo[i];
wallsFrom.RemoveAt(i);
wallsTo.RemoveAt(i);
// Break down wall if places on either side are in different sets,
// and join the sets
int iFrom = dict[from];
int iTo = dict[to];
if (arr[iFrom] != arr[iTo])
{
arr.JoinAt(iFrom, iTo);
SetWall(from, to, false);
}
}
}
