class Board():
def __init__(self, num_rows, num_cols):
self.num_rows = num_rows
self.num_cols = num_cols
self._grid = {}
self._hash = zobrist.EMPTY_BOARD
global neighbor_tables
dim = (num_rows, num_cols)
if dim not in neighbor_tables:
init_neighbor_table(dim)
if dim not in corner_tables:
init_corner_table(dim)
self.neighbor_table = neighbor_tables[dim]
self.corner_table = corner_tables[dim]
self.move_ages = MoveAge(self)
def neighbors(self, point):
return self.neighbor_table[point]
def corners(self, point):
return self.corner_table[point]
def place_stone(self, player, point):
assert self.is_on_grid(point)
if self._grid.get(point) is not None:
print('Illegal play on %s' % str(point))
assert self._grid.get(point) is None
# 0. Examine the adjacent points.
adjacent_same_color = []
adjacent_opposite_color = []
liberties = []
self.move_ages.increment_all()
self.move_ages.add(point)
for neighbor in self.neighbor_table[point]:
neighbor_string = self._grid.get(neighbor)
if neighbor_string is None:
liberties.append(neighbor)
elif neighbor_string.color == player:
if neighbor_string not in adjacent_same_color:
adjacent_same_color.append(neighbor_string)
else:
if neighbor_string not in adjacent_opposite_color:
adjacent_opposite_color.append(neighbor_string)
new_string = GoString(player, [point], liberties)
# tag::apply_zobrist[]
# 1. Merge any adjacent strings of the same color.
for same_color_string in adjacent_same_color:
new_string = new_string.merged_with(same_color_string)
for new_string_point in new_string.stones:
self._grid[new_string_point] = new_string
# Remove empty-point hash code.
self._hash ^= zobrist.HASH_CODE[point, None]
# Add filled point hash code.
self._hash ^= zobrist.HASH_CODE[point, player]
# end::apply_zobrist[]
# 2. Reduce liberties of any adjacent strings of the opposite
# color.
# 3. If any opposite color strings now have zero liberties,
# remove them.
for other_color_string in adjacent_opposite_color:
replacement = other_color_string.without_liberty(point)
if replacement.num_liberties:
self._replace_string(other_color_string.without_liberty(point))
else:
self._remove_string(other_color_string)
def _replace_string(self, new_string):
for point in new_string.stones:
self._grid[point] = new_string
def _remove_string(self, string):
for point in string.stones:
self.move_ages.reset_age(point)
# Removing a string can create liberties for other strings.
for neighbor in self.neighbor_table[point]:
neighbor_string = self._grid.get(neighbor)
if neighbor_string is None:
continue
if neighbor_string is not string:
self._replace_string(neighbor_string.with_liberty(point))
self._grid[point] = None
# Remove filled point hash code.
self._hash ^= zobrist.HASH_CODE[point, string.color]
# Add empty point hash code.
self._hash ^= zobrist.HASH_CODE[point, None]
def is_self_capture(self, player, point):
friendly_strings = []
for neighbor in self.neighbor_table[point]:
neighbor_string = self._grid.get(neighbor)
if neighbor_string is None:
# This point has a liberty. Can't be self capture.
return False
elif neighbor_string.color == player:
# Gather for later analysis.
friendly_strings.append(neighbor_string)
else:
if neighbor_string.num_liberties == 1:
# This move is real capture, not a self capture.
return False
if all(neighbor.num_liberties == 1 for neighbor in friendly_strings):
return True
return False
def will_capture(self, player, point):
for neighbor in self.neighbor_table[point]:
neighbor_string = self._grid.get(neighbor)
if neighbor_string is None:
continue
elif neighbor_string.color == player:
continue
else:
if neighbor_string.num_liberties == 1:
# This move would capture.
return True
return False
def is_on_grid(self, point):
return 1 <= point.row <= self.num_rows and \
1 <= point.col <= self.num_cols
def get(self, point):
"""Return the content of a point on the board.
Returns None if the point is empty, or a Player if there is a
stone on that point.
"""
string = self._grid.get(point)
if string is None:
return None
return string.color
def get_go_string(self, point):
"""Return the entire string of stones at a point.
Returns None if the point is empty, or a GoString if there is
a stone on that point.
"""
string = self._grid.get(point)
if string is None:
return None
return string
def __eq__(self, other):
return isinstance(other, Board) and \
self.num_rows == other.num_rows and \
self.num_cols == other.num_cols and \
self._hash() == other._hash()
def __deepcopy__(self, memodict={}):
copied = Board(self.num_rows, self.num_cols)
# Can do a shallow copy b/c the dictionary maps tuples
# (immutable) to GoStrings (also immutable)
copied._grid = copy.copy(self._grid)
copied._hash = self._hash
return copied
# tag::return_zobrist[]
def zobrist_hash(self):
return self._hash
class Board:
def __init__(self, num_rows, num_cols):
self.num_rows = num_rows
self.num_cols = num_cols
self._grid = {}
self._hash = zobrist.EMPTY_BOARD
global neighbor_tables
dim = (num_rows, num_cols)
if dim not in neighbor_tables:
init_neighbor_table(dim)
if dim not in corner_tables:
init_corner_table(dim)
self.neighbor_table = neighbor_tables[dim]
self.corner_table = corner_tables[dim]
self.move_ages = MoveAge(self)
def neighbors(self, point):
return self.neighbor_table[point]
def corners(self, point):
return self.corner_table[point]
def place_stone(self, player, point):
assert self.is_on_grid(point)
if self._grid.get(point) is not None:
print('Illegal play on %s' % str(point))
assert self._grid.get(point) is None
adjacent_same_color = []
adjacent_opposite_color = []
liberties = []
self.move_ages.increment_all()
self.move_ages.add(point)
for neighbor in self.neighbor_table[point]:
neighbor_string = self._grid.get(neighbor)
if neighbor_string is None:
liberties.append(neighbor)
elif neighbor_string.color == player:
if neighbor_string not in adjacent_same_color:
adjacent_same_color.append(neighbor_string)
else:
if neighbor_string not in adjacent_opposite_color:
adjacent_opposite_color.append(neighbor_string)
new_string = GoString(player, [point], liberties)
for same_color_string in adjacent_same_color:
new_string = new_string.merged_with(same_color_string)
for new_string_point in new_string.stones:
self._grid[new_string_point] = new_string
self._hash ^= zobrist.HASH_CODE[point, None]
self._hash ^= zobrist.HASH_CODE[point, player]
for other_color_string in adjacent_opposite_color:
replacement = other_color_string.without_liberty(point)
if replacement.num_liberties:
self._replace_string(other_color_string.without_liberty(point))
else:
self._remove_string(other_color_string)
def _replace_string(self, new_string):
for point in new_string.stones:
self._grid[point] = new_string
def _remove_string(self, string):
for point in string.stones:
self.move_ages.reset_age(point)
for neighbor in self.neighbor_table[point]:
neighbor_string = self._grid.get(neighbor)
if neighbor_string is None:
continue
if neighbor_string is not string:
self._replace_string(neighbor_string.with_liberty(point))
self._grid[point] = None
self._hash ^= zobrist.HASH_CODE[point, string.color]
self._hash ^= zobrist.HASH_CODE[point, None]
def is_self_capture(self, player, point):
friendly_strings = []
for neighbor in self.neighbor_table[point]:
neighbor_string = self._grid.get(neighbor)
if neighbor_string is None:
return False
elif neighbor_string.color == player:
friendly_strings.append(neighbor_string)
else:
if neighbor_string.num_liberties == 1:
return False
if all(neighbor.num_liberties == 1 for neighbor in friendly_strings):
return True
return False
def will_capture(self, player, point):
for neighbor in self.neighbor_table[point]:
neighbor_string = self._grid.get(neighbor)
if neighbor_string is None:
continue
elif neighbor_string.color == player:
continue
else:
if neighbor_string.num_liberties == 1:
return True
return False
def is_on_grid(self, point):
return 1 <= point.row <= self.num_rows and \
1 <= point.col <= self.num_cols
def get(self, point):
string = self._grid.get(point)
if string is None:
return None
return string.color
def get_go_string(self, point):
string = self._grid.get(point)
if string is None:
return None
return string
def __eq__(self, other):
return isinstance(other, Board) and \
self.num_rows == other.num_rows and \
self.num_cols == other.num_cols and \
self._hash() == other._hash()
def __deepcopy__(self, memodict=None):
if memodict is None:
memodict = {}
copied = Board(self.num_rows, self.num_cols)
copied._grid = copy.copy(self._grid)
copied._hash = self._hash
return copied
def zobrist_hash(self):
return self._hash