这段代码片段用于计算井字游戏中某个位置的最佳移动。我几乎理解了代码的每一部分,除了for循环中的条件,即minRating != LOSING_POSITION。这段代码来自于给定的伪代码实现。
moveT FindBestMove(stateT state, int depth, int & rating) {for (*each possible move or until you find a forced win*) { *Make the move. Evaluate the resulting position, adding one to the depth indicator. Keep track of the minimum rating so far, along with the corresponding move. Retract the move to restore the original state.* }*Store the move rating into the reference parameter.Return the best move.*}
我无法将for循环的第二个条件与给定的代码相匹配,该条件指出直到找到强制获胜。我无法找到这个事实与minRating != LOSING_POSITION之间的相似性
moveT FindBestMove(stateT state, int depth, int & rating) {Vector<moveT> moveList;GenerateMoveList(state, moveList);int nMoves = moveList.size();if (nMoves == 0) Error("No moves available");moveT bestMove;int minRating = WINNING_POSITION + 1;for (int i = 0; i < nMoves && minRating != LOSING_POSITION; i++) { moveT move = moveList[i]; MakeMove(state, move); int curRating = EvaluatePosition(state, depth + 1); if (curRating < minRating) { bestMove = move; minRating = curRating; } RetractMove(state, move); }rating = -minRating;return bestMove;}int EvaluatePosition(stateT state, int depth) {int rating;if (GameIsOver(state) || depth >= MAX_DEPTH) { return EvaluateStaticPosition(state);}FindBestMove(state, depth, rating);return rating;}
回答:
你的程序从将WINNING_POSITION
(我认为这是对手的胜利)赋值给minRating
开始,然后遍历所有移动,试图找到造成最大损害的移动,从而最小化minRating
。
当EvaluatePosition
返回LOSING_POSITION
时,这意味着这个移动在所有情况下都会导致对手输掉,因此可以终止搜索,并认为这个移动是最佳移动。
如果没有明显的LOSING_POSITIONS
,那么你的算法会根据静态评估选择“最佳”移动。