简易五子棋评估函数

void CFiveChessDlg::ComputerDown()
{
    int mode = 0, cur = 0, curX = 0, curY = 0, sum1 = 0, sum2 = 0;
    int x = 0, y = 0, cx = 0, cy = 0, cPrior = 0, prior = 0, flgL = 0, flgR = 0;

    for (x = 0; x < 15; x++)
    {
        for (y = 0; y < 15; y++)
        {    // 扫描全部空白点
            if (chessData[x][y] == 0)
            {
                prior = 0;
                for (mode = 1; mode < 5; mode++)    // 模式1为 — 向判断，模式2为 | 向判断
                {                            // 模式3为 \ 向判断，模式4为 / 向判断
                    sum1 = sum2 = 0;
                    flgL = flgR = 0;
                    curX = x;
                    curY = y; //改变模式后重置变量
                    for (cur = -4; cur <= 4; cur++)
                    {
                        if (mode == 1) //向→检查
                        {
                            curX = x + cur;
                            if (curX < 0) continue; //左越界继续
                            if (curX > 14) break;   //右越界停止
                        }
                        if (mode == 2) //向↓检查
                        {
                            curY = y + cur;
                            if (curY < 0) continue; //上越界继续
                            if (curY > 14) break;   //下越界停止
                        }
                        if (mode == 3) //向↘检查
                        {
                            curX = x + cur;
                            curY = y + cur;
                            if (curX < 0 || curY < 0) continue; // 左或上越界继续
                            if (curX > 14 || curY > 14) break;  // 右或下越界停止
                        }
                        if (mode == 4) //向↗检查
                        {
                            curX = x + cur;
                            curY = y - cur;
                            if (curX < 0 || curY>14) continue; // 左或下越界继续
                            if (curX > 14 || curY < 0) break;  // 右或上越界停止
                        }

                        // 初始化棋子标志，用于判断反色
                        if (cur < 0 && flgL == 0 && chessData[curX][curY] != 0)
                            flgL = chessData[curX][curY];

                        if (cur > 0 && flgR == 0 && chessData[curX][curY] != 0)
                            flgR = chessData[curX][curY];

                        if (cur < 0 && chessData[curX][curY] == (-flgL))
                        {
                            sum1 = -1;        // 左侧搜索到反色，相当于被堵住的棋
                            flgL = -flgL;    // 同时标记也取反
                        }

                        if (cur < 0 && chessData[curX][curY] == flgL)
                        {
                            sum1++; // 左侧搜索到同色
                        }

                        if (cur == -1 && sum1 > 0 && chessData[curX][curY] == 0)
                        {
                            sum1--; // 左一位搜索到空棋
                        }
                        if (cur == 1 && sum2 > 0 && chessData[curX][curY] == 0)
                        {
                            sum2--; // 右一位搜索到空棋
                        }

                        if (cur > 0 && flgL == flgR) // 如果左边的棋子和右边的同色
                        {
                            sum2 += sum1; // 用sum2代替sum1继续搜索
                            sum1 = 0;     // sum1置0以防重复相加和影响后面的cPrior
                        }

                        if (cur > 0 && chessData[curX][curY] == (-flgR))
                        {
                            sum2--; // 右边出现反色则，相当于被堵住的棋
                            break;   // 不需要继续搜索了
                        }

                        if (cur > 0 && chessData[curX][curY] == flgR)
                        {
                            sum2++;// 右侧搜索到同色
                        }

                    }
                    // 长连相对短连拥有绝对的优势
                    if (sum1 == 1) prior = prior + 1;
                    if (sum1 == 2) prior = prior + 10 - 2 * flgL; // 数目相同白棋优先
                    if (sum1 == 3) prior = prior + 100 - 20 * flgL;
                    if (sum1 == 4) prior = prior + 1000 - 200 * flgL;
                    if (sum2 == 1) prior = prior + 1;
                    if (sum2 == 2) prior = prior + 10 - 2 * flgR;
                    if (sum2 == 3) prior = prior + 100 - 20 * flgR;
                    if (sum2 == 4) prior = prior + 1000 - 200 * flgR;
                }

                if (prior > cPrior)
                {
                    cPrior = prior;
                    cx = x;
                    cy = y;
                }

                if (prior == cPrior && rand() < RAND_MAX / 5)
                {    // 除第一个棋外很少有优先级相等的点
                    cPrior = prior;
                    cx = x;
                    cy = y;
                }
            }
        }
    }

    PutDown(cx, cy); // 在得到的点下棋
}