@@ -216,66 +216,59 @@ def minmax(self, is_max=True, depth=0, alpha=-INF, beta=INF):
216216 if depth == self .depth or abs (score ) == Engine .INF :
217217 return score
218218
219- # find the minimum attainable value for the Goat
219+ # find the minimum attainable value for the minimizer
220220 if not is_max :
221- best_val = Engine .INF
222- 223221 for move in self .generate_move_list ():
224222 # first make the move
225223 self ._make_move (move )
226224
227225 # go deeper in the search tree recursively
228226 value = self .minmax (True , depth + 1 , alpha , beta )
229- best_val = min (best_val , value )
230- beta = min (beta , best_val )
227+ 228+ if value < beta :
229+ beta = value
230+ if depth == 0 :
231+ self .best_move = move
231232
232233 # then revert the move
233234 self ._revert_move (move )
234235
235236 # ab pruning
236- if beta <= alpha :
237- break
237+ if alpha >= beta :
238+ return beta
238239
239- return best_val
240+ return beta
240241
241242 # find the maximum attainable value for the maximizer
242243 else :
243- best_val = - Engine .INF
244- 245244 for move in self .generate_move_list ():
246245 # first make the move
247246 self ._make_move (move )
248247
249248 # go deeper in the search tree recursively
250249 value = self .minmax (False , depth + 1 , alpha , beta )
251- best_val = max (best_val , value )
252- alpha = max (alpha , best_val )
250+ 251+ if value > alpha :
252+ alpha = value
253+ if depth == 0 :
254+ self .best_move = move
253255
254256 # then revert the move
255257 self ._revert_move (move )
256258
257259 # ab pruning
258- if beta <= alpha :
259- break
260- 261- return best_val
262- 263- def find_best_move (self ):
264- score = 0
265- best_move = None
266- 267- for move in self .generate_move_list ():
268- # make the move
269- self ._make_move (move )
260+ if alpha >= beta :
261+ return alpha
270262
271- # is it the best move we've found so far?
272- if self .minmax (is_max = True ) > score :
273- best_move = move
263+ return alpha
274264
275- # revert the move
276- self ._revert_move (move )
265+ def best_tiger_move (self ):
266+ self .minmax ()
267+ return self .best_move
277268
278- return best_move
269+ def best_goat_move (self ):
270+ self .minmax (is_max = False )
271+ return self .best_move
279272
280273 def make_random_move (self ):
281274 import random
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