1+ import numpy as np
2+
3+ class Board :
4+ WHITE = - 1
5+ BLACK = 1
6+ EMPTY = 0
7+
8+ def __init__ (self ) -> None :
9+ '''Initiliaze the Othello game board with a 8x8 numpy matrix'''
10+ self .board = np .array ([0 ]* 8 , dtype = np .int8 ) # initiliasing 1D array with the first row of 8 zeroes
11+ self .board = self .board [np .newaxis , : ] # expanding 1D array to 2D array
12+ for _ in range (3 ): # increasing rows till 8
13+ self .board = np .concatenate ((self .board , self .board ), axis = 0 )
14+
15+ # initiliasing the centre squares
16+ self .board [3 , 3 ] = self .board [4 ,4 ] = Board .WHITE
17+ self .board [3 , 4 ] = self .board [4 ,3 ] = Board .BLACK
18+
19+ self .black_disc_count = 2
20+ self .white_disc_count = 2
21+
22+ def all_legal_moves (self , PLAYER : int ) -> set :
23+ '''Return all legal moves for the player'''
24+ OPPONENT = Board .WHITE if PLAYER == Board .BLACK else Board .BLACK
25+
26+ all_legal_moves = set ()
27+ for row in range (8 ):
28+ for col in range (8 ):
29+ if self .board [row , col ] == PLAYER :
30+ all_legal_moves .update (self .legal_moves (row , col ))
31+
32+ return all_legal_moves
33+
34+ def legal_moves (self , row : int , col : int ) -> list :
35+ '''Return all legal moves for the cell at the given position'''
36+ PLAYER = self .board [row , col ]
37+ OPPONENT = Board .WHITE if PLAYER == Board .BLACK else Board .BLACK
38+ legal_moves = list ()
39+
40+ # check for legal moves along the row of the cell
41+ if col >= 2 :
42+ i = col - 1
43+ while i >= 0 and self .board [row , i ] == OPPONENT :
44+ i -= 1
45+ if (i != col - 1 and i >= 0 ) and self .board [row , i ] == Board .EMPTY :
46+ legal_moves .append ((row , i ))
47+
48+ if col <= 5 :
49+ i = col + 1
50+ while i < 8 and self .board [row , i ] == OPPONENT :
51+ i += 1
52+ if (i != col + 1 and i < 8 ) and self .board [row , i ] == Board .EMPTY :
53+ legal_moves .append ((row , i ))
54+
55+ # check for legal moves along the column of the cell
56+ if row >= 2 :
57+ i = row - 1
58+ while i >= 0 and self .board [i , col ] == OPPONENT :
59+ i -= 1
60+ if (i != row - 1 and i >= 0 ) and self .board [i , col ] == Board .EMPTY :
61+ legal_moves .append ((i , col ))
62+
63+ if row <= 5 :
64+ i = row + 1
65+ while i < 8 and self .board [i , col ] == OPPONENT :
66+ i += 1
67+ if (i != row + 1 and i < 8 ) and self .board [i ,col ] == Board .EMPTY :
68+ legal_moves .append ((i , col ))
69+
70+ # check for legal moves along diagonals on which the cell lies
71+ if row >= 2 and col >= 2 : # diagonal from the cell towards top left
72+ r = row - 1
73+ c = col - 1
74+ while (r >= 0 and c >= 0 ) and self .board [r , c ] == OPPONENT :
75+ r -= 1
76+ c -= 1
77+ if (r != row - 1 and c != col - 1 ) and (r >= 0 and c >= 0 ) and self .board [r , c ] == Board .EMPTY :
78+ legal_moves .append ((r , c ))
79+
80+ if row >= 2 and col <= 5 : # diagonal from the cell towards top right
81+ r = row - 1
82+ c = col + 1
83+ while (r >= 0 and c < 8 ) and self .board [r , c ] == OPPONENT :
84+ r -= 1
85+ c += 1
86+ if (r != row - 1 and c != col + 1 ) and (r >= 0 and c < 8 ) and self .board [r , c ] == Board .EMPTY :
87+ legal_moves .append ((r , c ))
88+
89+ if row <= 5 and col <= 5 : # diagonal from the cell towards bottom right
90+ r = row + 1
91+ c = col + 1
92+ while (r < 8 and c < 8 ) and self .board [r , c ] == OPPONENT :
93+ r += 1
94+ c += 1
95+ if (r != row + 1 and c != col + 1 ) and (r < 8 and c < 8 ) and self .board [r , c ] == Board .EMPTY :
96+ legal_moves .append ((r , c ))
97+
98+ if row <= 5 and col >= 2 : # diagonal from the cell towards bottom left
99+ r = row + 1
100+ c = col - 1
101+ while (r < 8 and c >= 0 ) and self .board [r , c ] == OPPONENT :
102+ r += 1
103+ c -= 1
104+ if (r != row + 1 and c != col - 1 ) and (r < 8 and c >= 0 ) and self .board [r , c ] == Board .EMPTY :
105+ legal_moves .append ((r , c ))
106+
107+
108+ return legal_moves
109+
110+ def set_discs (self , row : int , col : int , PLAYER : int ) -> None :
111+ '''Set the discs on the board as per the move made on the given cell'''
112+ self .board [row , col ] = PLAYER
113+ OPPONENT = Board .WHITE if PLAYER == Board .BLACK else Board .BLACK
114+
115+ # outflanking pieces on the right
116+ c = col + 1
117+ while c < 8 and self .board [row , c ] == OPPONENT :
118+ c += 1
119+ if (c != col + 1 and c < 8 ) and self .board [row , c ] == PLAYER : # outflanking is legal
120+ self .board [row , col :c ] = PLAYER
121+
122+ # outflanking pieces on the left
123+ c = col - 1
124+ while c >= 0 and self .board [row , c ] == OPPONENT :
125+ c -= 1
126+ if (c != col - 1 and c >= 0 ) and self .board [row , c ] == PLAYER : # outflanking is ilegal
127+ self .board [row , c :col ] = PLAYER
128+
129+ # outflanking pieces below
130+ r = row + 1
131+ while r < 8 and self .board [r , col ] == OPPONENT :
132+ r += 1
133+ if (r != row + 1 and r < 8 ) and self .board [r , col ] == PLAYER : # outflanking is legal
134+ self .board [row :r , col ] = PLAYER
135+
136+ # outflanking pieces above
137+ r = row - 1
138+ while r >= 0 and self .board [r , col ] == OPPONENT :
139+ r -= 1
140+ if (r != row - 1 and r >= 0 ) and self .board [r , col ] == PLAYER : # outflanking is legal
141+ self .board [r :row , col ] = PLAYER
142+
143+ # outflanking pieces in the diagonal from the cell towards top left
144+ r = row - 1
145+ c = col - 1
146+ while (r >= 0 and c >= 0 ) and self .board [r , c ] == OPPONENT :
147+ r -= 1
148+ c -= 1
149+ if (r != row - 1 and c != col - 1 ) and (r >= 0 and c >= 0 ) and self .board [r , c ] == PLAYER : # outflanking is legal
150+ r = row - 1
151+ c = col - 1
152+ while self .board [r , c ] == OPPONENT :
153+ self .board [r , c ] = PLAYER
154+ r -= 1
155+ c -= 1
156+
157+ # outflanking pieces in the diagonal from the cell towards top right
158+ r = row - 1
159+ c = col + 1
160+ while (r >= 0 and c < 8 ) and self .board [r , c ] == OPPONENT :
161+ r -= 1
162+ c += 1
163+ if (r != row - 1 and c != col + 1 ) and (r >= 0 and c < 8 ) and self .board [r , c ] == PLAYER : # outflanking is legal
164+ r = row - 1
165+ c = col + 1
166+ while self .board [r , c ] == OPPONENT :
167+ self .board [r , c ] = PLAYER
168+ r -= 1
169+ c += 1
170+
171+ # outflanking pieces in the diagonal from the cell towards bottom right
172+ r = row + 1
173+ c = col + 1
174+ while (r < 8 and c < 8 ) and self .board [r , c ] == OPPONENT :
175+ r += 1
176+ c += 1
177+ if ( r != row + 1 and c != col + 1 ) and (r < 8 and c < 8 ) and self .board [r , c ] == PLAYER : # outflanking is legal
178+ r = row + 1
179+ c = col + 1
180+ while self .board [r , c ] == OPPONENT :
181+ self .board [r , c ] = PLAYER
182+ r += 1
183+ c += 1
184+
185+ # outflanking pieces in the diagonal from the cell towards bottom left
186+ r = row + 1
187+ c = col - 1
188+ while (r < 8 and c >= 0 ) and self .board [r , c ] == OPPONENT :
189+ r += 1
190+ c -= 1
191+ if (r != row + 1 and c != col - 1 ) and (r < 8 and c >= 0 ) and self .board [r , c ] == PLAYER : # outflanking is legal
192+ r = row + 1
193+ c = col - 1
194+ while self .board [r , c ] == OPPONENT :
195+ self .board [r , c ] = PLAYER
196+ r += 1
197+ c -= 1
198+
199+ # update disc counters
200+ self .black_disc_count = self .board [self .board > 0 ].sum ()
201+ self .white_disc_count = - self .board [self .board < 0 ].sum ()
202+
203+ def print_board (self ) -> None :
204+ print (self .board )
205+
206+ def reset_board (self ) -> None :
207+ self .board .fill (Board .EMPTY )
208+
209+ # initiliasing the centre squares
210+ self .board [3 , 3 ] = self .board [4 ,4 ] = Board .WHITE
211+ self .board [3 , 4 ] = self .board [4 ,3 ] = Board .BLACK
212+
213+ self .black_disc_count = self .white_disc_count = 2
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