BLACK = 1
WHITE = -1
EMPTY = 0


class Go:
	board = [[EMPTY]*19 for i in range(19)]
	
	def __init__(self):
		self.board = [[EMPTY]*19 for i in range(19)]
		self.move_count = 0
		self.temp = [[]]
	
	def move(self, color, y, x):
		"""Update the board with the specified move.

		:param int color: BLACK or WHITE
		:param int y: the row number
		:param int x: the column number
		:return: True on success, False on an invalid move"""
		if self.board[x][y] != EMPTY:
			return False

		self.board[x][y] = color

		for i, j in ((-1, 0), (1, 0), (0, -1), (0, 1)):
			self.temp = [[False]*19 for i in range(19)]
			if not self._flood_fill(-color, x + i, y + j):
				self._remove()
		self.temp = [[False]*19 for i in range(19)]
		if not self._flood_fill(color, x, y):
			self.board[x][y] = EMPTY
			return False
		self.move_count += 1
		return True

	def _flood_fill(self, color, x, y):
		if x < 0 or x > 18 or y < 0 or y > 18:
			return False
		if self.temp[x][y]:
			return False
		if self.board[x][y] == EMPTY:
			return True
		if self.board[x][y] != color:
			return False
		self.temp[x][y] = True

		return self._flood_fill(color, x-1, y) or \
			self._flood_fill(color, x+1, y) or \
			self._flood_fill(color, x, y-1) or \
			self._flood_fill(color, x, y+1)
	
	def _remove(self):
		for i in range(19):
			for j in range(19):
				if self.temp[i][j]:
					self.board[i][j] = EMPTY