写一个六子棋的博弈树C语言代码

以下是一个简单的六子棋博弈树的C语言代码，仅供参考：

#define N 6  // 棋盘大小
#define MAX_DEPTH 4  // 最大搜索深度

typedef struct {
    int x, y;
} Move;  // 一步棋的坐标

int board[N][N];  // 棋盘，0表示空，1表示黑棋，2表示白棋

int evaluate(int player) {
    // 评估当前局面的分数，player为当前玩家
    // 这里简单地返回棋盘上当前玩家棋子数与对手棋子数之差
    int count = 0;
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            if (board[i][j] == player) {
                count++;
            } else if (board[i][j] != 0) {
                count--;
            }
        }
    }
    return count;
}

int is_game_over() {
    // 判断是否游戏结束
    // 如果棋盘已满或者有一方连成六个棋子，则游戏结束
    int i, j, k, l;
    for (i = 0; i < N; i++) {
        for (j = 0; j < N; j++) {
            if (board[i][j] == 0) {
                continue;
            }
            for (k = -1; k <= 1; k++) {
                for (l = -1; l <= 1; l++) {
                    if (k == 0 && l == 0) {
                        continue;
                    }
                    int x = i, y = j, count = 0;
                    while (x >= 0 && x < N && y >= 0 && y < N && board[x][y] == board[i][j]) {
                        count++;
                        x += k;
                        y += l;
                    }
                    if (count >= 6) {
                        return board[i][j];
                    }
                }
            }
        }
    }
    for (i = 0; i < N; i++) {
        for (j = 0; j < N; j++) {
            if (board[i][j] == 0) {
                return 0;
            }
        }
    }
    return 3;  // 棋盘已满，平局
}

int search(int depth, int alpha, int beta, int player, Move *best_move) {
    // 利用博弈树搜索算法搜索最佳棋步
    int i, j, score, max_score = -1000000, min_score = 1000000;
    Move move;
    int game_over = is_game_over();
    if (depth == 0 || game_over != 0) {
        return evaluate(player);
    }
    for (i = 0; i < N; i++) {
        for (j = 0; j < N; j++) {
            if (board[i][j] != 0) {
                continue;
            }
            board[i][j] = player;
            score = search(depth - 1, alpha, beta, 3 - player, &move);
            board[i][j] = 0;
            if (player == 1) {
                if (score > max_score) {
                    max_score = score;
                    if (depth == MAX_DEPTH) {
                        best_move->x = i;
                        best_move->y = j;
                    }
                }
                alpha = alpha > max_score ? alpha : max_score;
                if (max_score >= beta) {
                    return max_score;
                }
            } else {
                if (score < min_score) {
                    min_score = score;
                }
                beta = beta < min_score ? beta : min_score;
                if (min_score <= alpha) {
                    return min_score;
                }
            }
        }
    }
    return player == 1 ? max_score : min_score;
}

int main() {
    // 初始化棋盘
    int i, j;
    for (i = 0; i < N; i++) {
        for (j = 0; j < N; j++) {
            board[i][j] = 0;
        }
    }
    // 玩家为黑棋，电脑为白棋
    int player = 1;
    while (1) {
        if (player == 1) {
            // 玩家落子
            int x, y;
            printf("请输入落子位置：");
            scanf("%d%d", &x, &y);
            if (board[x][y] != 0) {
                printf("该位置已有棋子，请重新输入！\n");
                continue;
            }
            board[x][y] = 1;
        } else {
            // 电脑落子
            Move best_move;
            search(MAX_DEPTH, -1000000, 1000000, 2, &best_move);
            board[best_move.x][best_move.y] = 2;
            printf("电脑落子：%d %d\n", best_move.x, best_move.y);
        }
        // 打印当前棋盘
        printf("  ");
        for (i = 0; i < N; i++) {
            printf("%c ", 'A' + i);
        }
        printf("\n");
        for (i = 0; i < N; i++) {
            printf("%d ", i + 1);
            for (j = 0; j < N; j++) {
                if (board[i][j] == 0) {
                    printf(". ");
                } else if (board[i][j] == 1) {
                    printf("X ");
                } else {
                    printf("O ");
                }
            }
            printf("\n");
        }
        // 判断游戏是否结束
        int game_over = is_game_over();
        if (game_over != 0) {
            if (game_over == 1) {
                printf("你赢了！\n");
            } else if (game_over == 2) {
                printf("电脑赢了！\n");
            } else {
                printf("平局！\n");
            }
            break;
        }
        // 切换玩家
        player = 3 - player;
    }
    return 0;
}