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"""Representation of a board. Contains played stones and captured stones."""
from copy import deepcopy
from imago.data.enums import Player
def _getNewBoard(height, width):
"""Return a new board."""
board = []
for row in range(height):
board.append([])
for _ in range(width):
board[row].append(Player.EMPTY)
return board
class GameBoard:
"""Logic and state related to the board."""
def __init__(self, height, width):
self.board = _getNewBoard(height, width)
self.capturesBlack = 0
self.capturesWhite = 0
def getBoard(self):
"""Gets the matrix representing the board."""
return self.board
def getBoardHeight(self):
"""Returns the number of rows in the board."""
return len(self.board)
def getBoardWidth(self):
"""Returns the number of columns of the first row of the board. This number should
be the same for all the rows."""
return len(self.board[0])
def getDeepCopy(self):
"""Returns a copy GameBoard."""
newBoard = GameBoard(self.getBoardHeight(), self.getBoardWidth())
newBoard.capturesBlack = self.capturesBlack
newBoard.capturesWhite = self.capturesWhite
newBoard.board = deepcopy(self.board)
return newBoard
def getGroupLiberties(self, row, col):
"""Returns the empty vertices adjacent to the group occupying a vertex (its
liberties) as a set. An empty set is returned if the vertex is empty.
"""
groupColor = self.board[row][col]
if groupColor == Player.EMPTY:
return set()
emptyCells = set()
exploredCells = set()
self._exploreLiberties(row, col, groupColor, emptyCells, exploredCells)
return emptyCells
def getGroupLibertiesCount(self, row, col):
"""Returns the number of liberties of a group."""
return len(self.getGroupLiberties(row, col))
def _exploreLiberties(self, row, col, groupColor, emptyCells, exploredCells):
"""Adds surrounding empty cells to array if they have not been added yet
and explores adjacent occupied cells of the same group.
"""
if (row, col) in exploredCells:
return
exploredCells.add((row, col))
cellColor = self.board[row][col]
if cellColor != groupColor:
if cellColor == Player.EMPTY:
emptyCells.add((row, col))
return
for side in ((-1,0), (1,0), (0,-1), (0,1)):
rowToExplore = row + side[0]
colToExplore = col + side[1]
if self.isMoveInBoardBounds(rowToExplore, colToExplore):
self._exploreLiberties(rowToExplore, colToExplore, groupColor,
emptyCells, exploredCells)
def getGroupVertices(self, row, col):
"""
Returns a set containing the cells occupied by the group in the given cell.
This is also valid if the cell is empty."""
groupColor = self.board[row][col]
cells = set()
self.__exploreGroup(row, col, groupColor, cells)
return cells
def getGroupVerticesCount(self, row, col):
"""Returns the number of cells of a group."""
return len(self.getGroupVertices(row, col))
def __exploreGroup(self, row, col, groupColor, cells):
if self.board[row][col] != groupColor or (row, col) in cells:
return
cells.add((row, col))
for side in ((-1,0), (1,0), (0,-1), (0,1)):
rowToExplore = row + side[0]
colToExplore = col + side[1]
if self.isMoveInBoardBounds(rowToExplore, colToExplore):
self.__exploreGroup(rowToExplore, colToExplore, groupColor, cells)
def moveAndCapture(self, row, col, player):
"""Checks surrounding captures of a move, removes them and returns a set
containing the vertices where stones were captured.
"""
try:
if (row < 0 or row >= self.getBoardHeight()
or col < 0 or col >= self.getBoardWidth()):
raise RuntimeError("[ERROR] Move and capture: out of bounds (%d, %d)" % (row, col))
except Exception as err:
raise RuntimeError("[ERROR] Move and capture: Wrong input: %s" % err)
self.board[row][col] = player
captured = set()
for side in ((-1,0), (1,0), (0,-1), (0,1)):
rowToExplore = row + side[0]
colToExplore = col + side[1]
if self.isMoveInBoardBounds(rowToExplore, colToExplore):
if (self.board[rowToExplore][colToExplore] != player
and self.board[rowToExplore][colToExplore] != Player.EMPTY
and self.getGroupLibertiesCount(rowToExplore, colToExplore) == 0):
captured.update(self.__captureGroup(rowToExplore, colToExplore))
return captured
def __captureGroup(self, row, col):
"""Removes all the stones from the group occupying the given cell and returns a
set containing them.
"""
cellsToCapture = self.getGroupVertices(row, col)
for cell in cellsToCapture:
self.board[cell[0]][cell[1]] = Player.EMPTY
return cellsToCapture
def isMoveInBoardBounds(self, row, col):
"""Returns True if move is inside board bounds, false otherwise."""
return 0 <= row < self.getBoardHeight() and 0 <= col < self.getBoardWidth()
def isCellEmpty(self, row, col):
"""Returns True if cell is empty, false otherwise."""
return self.board[row][col] == Player.EMPTY
def isCellEye(self, row, col):
"""Returns the surrounding color if the cell is part of an eye and Player.EMTPY
otherwise.
"""
# if isCellEmpty && all adjacent to group are same color
if not self.isCellEmpty(row, col):
return Player.EMPTY
groupCells = self.getGroupVertices(row, col)
surroundingColor = Player.EMPTY
# Check surrounding cells of each cell in the group
for cell in groupCells:
for side in ((-1,0), (1,0), (0,-1), (0,1)):
rowChecked = cell[0]+side[0]
colChecked = cell[1]+side[1]
if self.isMoveInBoardBounds(rowChecked, colChecked):
otherColor = self.board[rowChecked][colChecked]
if otherColor != Player.EMPTY:
if surroundingColor == Player.EMPTY:
surroundingColor = otherColor
elif surroundingColor != otherColor:
return Player.EMPTY
return surroundingColor
def isMoveSuicidal(self, row, col, player):
"""Returns True if move is suicidal."""
# Check vertex is empty
if not self.isCellEmpty(row, col):
raise RuntimeError("Cell to play should be empty when checking for suicide.")
# Temporarily play and capture
self.board[row][col] = player
groupLiberties = self.getGroupLibertiesCount(row, col)
captured = self.moveAndCapture(row, col, player)
illegal = False
# If move didn't capture anything and its group is left without liberties, it's
# suicidal
if len(captured) == 0 and groupLiberties == 0:
illegal = True
# Restore captured stones
for vertex in captured:
self.board[vertex[0]][vertex[1]] = Player.otherPlayer(player)
# Remove temporarily played stone
self.board[row][col] = Player.EMPTY
return illegal
def isMoveKoIllegal(self, row, col, player, prevBoards):
"""Returns True if move is illegal because of ko."""
# Check vertex is empty
if not self.isCellEmpty(row, col):
raise RuntimeError("Cell to play should be empty when checking for ko.")
illegal = False
# Temporarily play and capture for comparisons
captured = self.moveAndCapture(row, col, player)
# Check previous boards
for prevBoard in prevBoards:
# A ko is possible in boards where the stone to play exists
if prevBoard.board[row][col] == player:
if self.equals(prevBoard):
illegal = True
# Restore captured stones
for vertex in captured:
self.board[vertex[0]][vertex[1]] = Player.otherPlayer(player)
# Remove temporarily played stone
self.board[row][col] = Player.EMPTY
return illegal
def isPlayable(self, row, col, player, prevBoards):
"""Determines if a move is playable."""
if not self.isMoveInBoardBounds(row, col):
return False, "Move outside board bounds."
if not self.isCellEmpty(row, col):
return False, "Vertex is not empty."
if self.isMoveSuicidal(row, col, player):
return False, "Move is suicidal."
if self.isMoveKoIllegal(row, col, player, prevBoards):
return False, "Illegal by ko rule."
return True, ""
def isSensible(self, row, col, player, prevBoards):
"""Determines if a move is playable and sensible."""
playable, playableText = self.isPlayable(row, col, player, prevBoards)
if not playable:
return playable, playableText
if ( self.getGroupVerticesCount(row, col) == 1
and self.isCellEye(row, col) == player ):
return False, "Move fills own eye."""
return True, ""
def score(self):
"""Gets the current score given by the already surrounded territory for Japanese
rules. The format of the returned score is (black, white).
"""
scores = []
for player in Player:
while len(scores) <= player.value:
scores.append(0)
checkedVertices = set()
for row in range(0, self.getBoardHeight()):
for col in range(0, self.getBoardWidth()):
if not (row, col) in checkedVertices:
group = self.getGroupVertices(row, col)
for cell in group:
checkedVertices.add(cell)
surroundingColor = self.isCellEye(row, col)
if surroundingColor != Player.EMPTY:
scores[surroundingColor.value] += len(group)
return (scores[Player.BLACK.value], scores[Player.WHITE.value])
def equals(self, otherBoard):
"""Returns true if this board is equal to another board. Only takes into account
dimensions and placed stones.
"""
if ( self.getBoardHeight() != otherBoard.getBoardHeight()
or self.getBoardWidth() != otherBoard.getBoardWidth() ):
return False
for row in range(self.getBoardHeight()):
for col in range(self.getBoardWidth()):
if self.board[row][col] != otherBoard.board[row][col]:
return False
return True
def toString(self):
"""Returns a representation of the state of the board as a string."""
colTitle = 'A'
rowTitlePadding = 2
if self.getBoardHeight() >= 10:
firstRowPadding = 2
else:
firstRowPadding = 1
# Print column names
rowText = " " * (rowTitlePadding + firstRowPadding)
for col in range(self.getBoardWidth()):
rowText += colTitle + " "
colTitle = chr(ord(colTitle)+1)
if colTitle == "I": # Skip I
colTitle = "J"
output = rowText
# Print rows
rowTitle = self.getBoardHeight()
for row in self.board:
rowText = ""
for col in row:
rowText += cellToString(col) + " "
output += '\n%d%s%s' % (rowTitle, " " * rowTitlePadding, rowText)
rowTitle -= 1
if rowTitle == 9:
rowTitlePadding += 1
return output
def printBoard(self):
"""Print the board."""
print(self.toString())
def cellToString(code):
"""Returns the text representation of a cell."""
if code == Player.WHITE:
return 'W'
if code == Player.BLACK:
return 'B'
return 'ยท'
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