Monkey黑白棋 所使用的经典算法(源代码)

       /**//// <summary>


        /// ＡｌｐｈａＢｅｔａ剪枝法


        /// </summary>


        /// <returns></returns>


        private int AlphaBetaSearch(int curDepth, int alpha, int beta)




        ...{


            lock (this)




            ...{


                if (curDepth >= Depth || times >= MaxTimes)




                ...{


                    times++;


                    //开局或中局对棋盘评分,boardState指定是开局还是中局


                    MonkeyOthello.BoardFX(boardState);


                    SetNums(0);


                    SetNums(1);


                    //返回估值


                    return SetScore(boardState);


                }


                else




                ...{


                    //if (times < MaxTimes)


                    //{


                    //    StaticObject.ThinkingProgressBar.Value = times;


                    //}


                    if (!MonkeyOthello.CanDown())




                    ...{


                        //如果没棋可下,交换对手


                        MonkeyOthello.CurrentColor = 1 - MonkeyOthello.CurrentColor;


                        if (!MonkeyOthello.CanDown())




                        ...{


                            //双方都没棋可下,则不用再往下搜索


                            MonkeyOthello.CurrentColor = 1 - MonkeyOthello.CurrentColor;


                            //中局就已经结束游戏,获取中局的结果


                            GameResult result = MonkeyOthello.GetMidGameResult((int)MonkeyOthello.CurrentColor);


                            //中局就已经结束游戏,返回游戏结束的估值


                            return EvalGameOver(result, beta);


                        }


                        else




                        ...{


                            //其中一方无棋可下,继续由对方下


                            return -AlphaBetaSearch(curDepth + 1, -beta, -alpha);


                            //alpha = -beta; beta = -alpha; curDepth++;


                        }


                    }


                    //进栈(当前的所有棋步)


                    AllStepStack.Push(new Stack<Step>(MonkeyOthello.Mobility));


                    //当前估值


                    int score;


                    //棋步数量


                    int Num = MonkeyOthello.MobilityNum[(int)MonkeyOthello.CurrentColor];


                    for (int i = 0; i < Num; i++)




                    ...{


                        //获取没有访问过的棋步


                        Step step = GetNotVisitedStep();


                        //模拟下一步棋


                        MonkeyOthello.DownStones(step);


                        // 搜索下一步(递归)


                        score= -AlphaBetaSearch(curDepth + 1, -beta, -alpha);


                        //退一步


                        MonkeyOthello.Reback();


                        //搜索到比上次高的估值,替换


                        if (score > alpha)




                        ...{


                            alpha = score;


                            //如果认为已经赢定,则可以终止搜索


                            if (score >= beta)


                                break;


                        }


                    }


                    //退栈(当前的所有棋步)


                    AllStepStack.Pop();


                    return alpha;


                }


            }


        }

      我把它用在开局和中局的思考,当然开局跟中局的评估函数有区别

     而当离游戏还有10-12步时,用它来搜索最大赢子数.