在一定深度的 Minimax 树中计算移动分数

问：

我已经用 C 语言实现了一个国际象棋游戏，具有以下结构：

move - 表示在 char 板上从 （a，b） 到 （c，d） 的移动[8][8] （国际象棋棋盘）

移动 - 这是一个带有头部和反面的移动链表。

变量：playing_color 是 'W' 或 'B'。 minimax_depth是之前设置的最小最大深度。

这是我的 Minimax 函数的代码，带有 alpha-beta 剪枝和 getMoveScore 函数，它应该返回之前设置的某个minimax_depth的 Minimax 树中的移动分数。

此外，我还使用了 getBestMoves 函数，我也会在这里列出该函数，它基本上会在 Minimax 算法中找到最佳移动并将它们保存到全局变量中，以便我以后能够使用它们。

我必须补充一点，我将在此处添加的三个函数中列出的所有函数都正常工作并经过测试，因此问题要么是 alphabetaMax 算法的逻辑问题，要么是 getBestMoves/getMoveScore。

问题主要在于，当我在深度 N 处获得最佳步数时（在某种程度上也没有正确计算），然后使用 getMoveScore 函数检查它们在相同深度上的分数时，我得到的分数与这些实际最佳步数的分数不匹配。我花了几个小时来调试它，但看不到错误，我希望也许有人能给我一个关于找到问题的提示。

代码如下：

/*
* Getting best possible moves for the playing color with the minimax algorithm
*/
moves* getBestMoves(char playing_color){
    //Allocate memory for the best_moves which is a global variable to fill it in   a minimax algorithm//
    best_moves = calloc(1, sizeof(moves));
    //Call an alpha-beta pruned minimax to compute the best moves//
    alphabeta(playing_color, board, minimax_depth, INT_MIN, INT_MAX, 1);
    return best_moves;
}

/*
* Getting the score of a given move for a current player
*/
int getMoveScore(char playing_color, move* curr_move){
    //Allocate memory for best_moves although its not used so its just freed    later//
    best_moves = calloc(1, sizeof(moves));
    int score;
    char board_cpy[BOARD_SIZE][BOARD_SIZE];
    //Copying a a current board and making a move on that board which score I   want to compute//
    boardCopy(board, board_cpy);
    actualBoardUpdate(curr_move, board_cpy, playing_color);
    //Calling the alphabeta Minimax now with the opposite color , a board after     a given move and as a minimizing player, because basicly I made my move so  its now the opponents turn and he is the minimizing player//
    score = alphabeta(OppositeColor(playing_color), board_cpy, minimax_depth, INT_MIN, INT_MAX, 0);
    freeMoves(best_moves->head);
    free(best_moves);
    return score;
}

/*
* Minimax function - finding the score of the best move possible from the input board
*/
int alphabeta(char playing_color, char curr_board[BOARD_SIZE][BOARD_SIZE], int depth,int alpha,int beta, int maximizing) {
    if (depth == 0){
        //If I'm at depth 0 I'm evaluating the current board with my scoring            function//
        return scoringFunc(curr_board, playing_color);
    }
    int score;
    int max_score;
    char board_cpy[BOARD_SIZE][BOARD_SIZE];
    //I'm getting all the possible legal moves for the playing color//
    moves * all_moves = getMoves(playing_color, curr_board);
    move* curr_move = all_moves->head;
    //If its terminating move I'm evaluating board as well, its separate from depth == 0 because    only here I want to free memory//
    if (curr_move == NULL){
        free(all_moves);
        return scoringFunc(curr_board,playing_color);
    }
    //If maximizing player is playing//
    if (maximizing) {
        score = INT_MIN;
        max_score = score;
        while (curr_move != NULL){
            //Make the move and call alphabeta with the current board               after the move for opposite color and !maximizing player//
            boardCopy(curr_board, board_cpy);
            actualBoardUpdate(curr_move, board_cpy, playing_color);
            score = alphabeta(OppositeColor(playing_color), board_cpy, depth - 1,alpha,beta, !maximizing);
            
            alpha = MAX(alpha, score);
            if (beta <= alpha){
                break;
            }
            //If I'm at the maximum depth I want to get current player              best moves//
            if (depth == minimax_depth){
                move* best_move;
                //If I found a move with a score that is bigger then                    the max score, I will free all previous moves and                   append him, and update the max_score//
                if (score > max_score){
                    max_score = score;
                    freeMoves(best_moves->head);
                    free(best_moves);
                    best_moves = calloc(1, sizeof(moves));
                    best_move = copyMove(curr_move);
                    concatMoves(best_moves, best_move);
                }
                //If I have found a move with the same score and want                   to concatenate it to a list of best moves//
                else if (score == max_score){
                    best_move = copyMove(curr_move);
                    concatMoves(best_moves, best_move);
                }
                
            }
            //Move to the next move//
            curr_move = curr_move->next;
        }
        freeMoves(all_moves->head);
        free(all_moves);
        return alpha;
    }
    else {
        //The same as maximizing just for a minimizing player and I dont want       to look for best moves here because I dont want to minimize my          outcome//
        score = INT_MAX;
        while (curr_move != NULL){
            boardCopy(curr_board, board_cpy);
            actualBoardUpdate(curr_move, board_cpy, playing_color);
            score = alphabeta(OppositeColor(playing_color), board_cpy, depth - 1,alpha,beta, !maximizing);
            beta = MIN(beta, score);
            if (beta <= alpha){
                break;
            }
            curr_move = curr_move->next;
        }
        freeMoves(all_moves->head);
        free(all_moves);
        return beta;
    }
}

正如尤金所指出的，我在这里添加一个例子：http://imageshack.com/a/img910/4643/fmQvlm.png

我目前是白人玩家，我只有 king-k 和 queen-q，相反的颜色有 king-K 和 rook-R。显然，我在这里最好的举动是吃一辆车或至少引起检查。棋子的动作经过测试，效果很好。尽管当我在深度 3 调用get_best_moves函数时，我在该深度得到了很多不必要的动作和负分。也许现在更清楚了。谢谢！