sawine@3: class Grid(object):
sawine@3: 
sawine@3: 	def __init__(self):
sawine@3: 		self.cells = {}
sawine@5: 		self.valuemap = {}
sawine@3: 		self.minx = 0
sawine@3: 		self.maxx = 0
sawine@3: 		self.miny = 0
sawine@3: 		self.maxy = 0
sawine@3: 
sawine@3: 	def set(self, pos, value=1):
sawine@5: 		if pos in self.cells and value != self.cells[pos]:
sawine@5: 			self.clear(pos)
sawine@5: 		if not pos in self.cells:
sawine@3: 			self.cells[pos] = value
sawine@5: 			if value in self.valuemap:
sawine@5: 				self.valuemap[value].append(pos)
sawine@5: 			else:
sawine@5: 				self.valuemap[value] = [pos]
sawine@3: 			self.update(pos)
sawine@3: 		return self
sawine@3: 
sawine@3: 	def clear(self, pos):
sawine@5: 		if pos in self.cells: 
sawine@5: 			self.valuemap[self.cells[pos]].remove(pos)
sawine@3: 			del self.cells[pos]
sawine@3: 			self.update(pos)
sawine@3: 		return self
sawine@3: 
sawine@3: 	def update(self, (x, y)):
sawine@3: 		self.minx = min(x, self.minx)
sawine@3: 		self.maxx = max(x, self.maxx)
sawine@3: 		self.miny = min(y, self.miny)
sawine@3: 		self.maxy = max(y, self.maxy)
sawine@3: 		return self
sawine@3: 
sawine@3: 	def width(self):
sawine@3: 		return self.maxx - self.minx + 1
sawine@3: 
sawine@3: 	def height(self):
sawine@3: 		return self.maxy - self.miny + 1
sawine@3: 
sawine@3: 	def __len__(self):
sawine@3: 		return len(self.cells)
sawine@3: 
sawine@3: 	def __str__(self):
sawine@3: 		pass