class Go:
  EMPTY=0
  BLACK=1
  WHITE=-1
  
  ## Initializes self.board to a list[r][c]=Go.EMPTY.
  def __init__(self,boardSize=19):
    self.boardSize=boardSize
    self.board=[[Go.EMPTY]*self.boardSize for x in self.board]
  
  ## Executes a move.
  #  
  #  Doesn't check for kos. Suicide not allowed.
  #  
  #  @param color Go.BLACK or Go.WHITE
  #  @return True on success, False on failure (illegal move)
  def move(self,color,row,col):
    if self.board[row][col]!=Go.EMPTY: return False

    self.board[row][col]=color

    # capture neighbors
    for r,c in ((-1,0),(1,0),(0,-1),(0,1)):
      self.temp=[[False]*self.boardSize for x in self.board]
      if not self._floodFill(-color,row+r,col+c): self._remove()
    
    # check for suicide
    self.temp=[[False]*self.boardSize for x in self.board]
    if not self._floodFill(color,row,col):
      self.board[row][col]=Go.EMPTY
      return False
    return True
    
  ## Checks for liberties of a stone at given coordinates.
  #  
  #  The stone's group is marked with True in self.temp, ready for capture if needed. Recursively called for stone's neighbors.
  #  
  #  @return True if alive, False if captured
  def _floodFill(self,color,row,col):
    if col<0 or col>=self.boardSize or row<0 or row>=self.boardSize: return False # out of range
    if self.temp[row][col]: return False # already visited
    if self.board[row][col]==Go.EMPTY: return True # found a liberty
    if self.board[row][col]!=color: return False # opponent's stone
    self.temp[row][col]=True # set visited
    return self._floodFill(color,row,col-1) or self._floodFill(color,row,col+1) or self._floodFill(color,row-1,col) or self._floodFill(color,row+1,col) # check neighbors
  
  ## Removes stones at coordinates marked with True in self.temp.
  def _remove(self):
    for r in range(self.boardSize):
      for c in range(self.boardSize):
        if self.temp[r][c]: self.board[r][c]=Go.EMPTY