alphabetaandtt.cpp

重庆大学出版社出版的《PC游戏编程（人机博弈）》一书的配套光盘内容。本书是一本专论机器搏奔的作品。详细披露了编写人机对奔程序的原理

// COPYRIGHT NOTES
// ---------------
// This source code is a part of chess which is an example of <Game Programing guide>.
// You may use, compile or redistribute it as part of your application 
// for free. 
// You cannot redistribute sources without the official agreement of the author. 
// If distribution of you application which contents code below was occured, place 
// e-mail <[e-mail]> on it is to be appreciated.
// This code can be used WITHOUT ANY WARRANTIES on your own risk.
// 
// Spring Wang <[e-mail]>

// ---------------
// 版权声明
// ---------------
// 本文件所含之代码是《人机博弈程序设计指南》的范例程序中国象棋的一部分
// 您可以免费的使用, 编译 或者作为您应用程序的一部分。 
// 但，您不能在未经作者书面许可的情况下分发此源代码。 
// 如果您的应用程序使用了这些代码，在您的应用程序界面上 
// 放入 e-mail <[e-mail]> 是令人欣赏的做法。
// 此代码并不含有任何保证，使用者当自承风险。
// 
// 王小春 <[e-mail]>

// AlphaBetaAndTT.cpp: implementation of the CAlphaBetaAndTT class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "chess.h"
#include "AlphaBetaAndTT.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////
CAlphaBetaAndTT::CAlphaBetaAndTT()
{
}

CAlphaBetaAndTT::~CAlphaBetaAndTT()
{
}


CAlphaBetaAndTT::SearchAGoodMove(BYTE position[10][9])
{
	memcpy(CurPosition, position, 90);
	CalculateInitHashKey(CurPosition);
	m_nMaxDepth = m_nSearchDepth;
	alphabeta(m_nMaxDepth, -20000, 20000);
	MakeMove(&m_cmBestMove);
	memcpy(position, CurPosition, 90);
}


int CAlphaBetaAndTT::alphabeta(int depth, int alpha, int beta)
{
	int score;
	int Count,i;
	BYTE type;
	int side;

	i = IsGameOver(CurPosition, depth);
	if (i != 0)
		return i;

	side = (m_nMaxDepth-depth)%2;

	score = LookUpHashTable(alpha, beta, depth, side); 
	if (score != 66666) 
		return score;

	if (depth <= 0)	//叶子节点取估值
	{
		score = m_pEval->Eveluate(CurPosition, side );
		EnterHashTable(exact, score, depth, side );
		return score;
	}



	Count = m_pMG->CreatePossibleMove(CurPosition, depth, side);
	
    int eval_is_exact = 0;

	for (i=0;i<Count;i++) 
	{
		Hash_MakeMove(&m_pMG->m_MoveList[depth][i], CurPosition);
		type = MakeMove(&m_pMG->m_MoveList[depth][i]);
		
		score = -alphabeta(depth - 1, -beta, -alpha);

		Hash_UnMakeMove(&m_pMG->m_MoveList[depth][i],type, CurPosition); 
		UnMakeMove(&m_pMG->m_MoveList[depth][i],type); 
        if (score >= beta) 
		{
			EnterHashTable(lower_bound, score, depth,side);
            return score;
        }

		if (score > alpha)
		{
			alpha = score;
			eval_is_exact = 1;
			if(depth == m_nMaxDepth)
				m_cmBestMove = m_pMG->m_MoveList[depth][i];
		}

	}

    if (eval_is_exact) 
		EnterHashTable(exact, alpha, depth,side);
    else 
		EnterHashTable(upper_bound, alpha, depth,side);
	return alpha;
}