from util import EMPTY


## Utility class for finding continuous regions on a Go.board.
class HelperBoard:
	def __init__(self,board):
		self._refBoard=board # Go.board, readonly
		self._boardSize=len(board)
		self._board=[[EMPTY]*self._boardSize for i in range(self._boardSize)]
		self._usedCoords=[0]*(self._boardSize**2)*2
		self._usedCount=0

	def floodFill(self,filling,r,c,needle=None):
		if c<0 or c>=self._boardSize or r<0 or r>=self._boardSize: return False # out of range
		if self._board[r][c]: return False # already visited
		if self._refBoard[r][c]==needle: return True # found something
		if self._refBoard[r][c]!=filling: return False # out of area boundary
		self._board[r][c]=True # set visited
		self._usedCoords[self._usedCount*2]=r
		self._usedCoords[self._usedCount*2+1]=c
		self._usedCount+=1

		# check neighbors
		return self.floodFill(filling,r,c-1) or \
			self.floodFill(filling,r,c+1) or \
			self.floodFill(filling,r-1,c) or \
			self.floodFill(filling,r+1,c)

	def continuousArea(self):
		for i in range(self._usedCount):
			yield (self._usedCoords[i*2],self._usedCoords[i*2+1])

	def clear(self):
		for i in range(self._usedCount):
			(r,c)=(self._usedCoords[i*2],self._usedCoords[i*2+1])
			self._board[r][c]=EMPTY
		self._usedCount=0