Initial fortress work (mazes).

unionfind.lua

@@ -0,0 +1,48 @@
+function table.shuffle(self)
+	local j
+	local t = self
+
+	for i = #t, 2, -1 do
+		j = math.random(i)
+		t[i], t[j] = t[j], t[i]
+	end
+end
+
+
+function unionfind(max)
+	local u = { _parent = {}, _rank = {} }
+
+	for i = 1, max do
+		u._parent[i] = i
+		u._rank[i] = 1
+	end
+
+	u.find = function(self, i)
+		local p = self._parent[i]
+		if i == p then
+			return i
+		end
+		self._parent[i] = self:find(p)
+		return self._parent[i]
+	end
+
+	u.union = function(self, i, j)
+		local root1 = self:find(i)
+		local root2 = self:find(j)
+
+		if root1 == root2 then
+			return
+		end
+
+		if self._rank[root1] > self._rank[root2] then
+			self._parent[root2] = root1
+		elseif self._rank[root2] > self._rank[root1] then
+			self._parent[root1] = root2
+		else
+			self._parent[root2] = root1
+			self._rank[root1] = self._rank[root1] + 1
+		end
+	end
+
+	return u
+end