protected Point FindMove()
{
Point move;
searchtimes = 0;
if (turnCount == 0)
{
return(new Point(7, 7));
}
else if (turnCount == 1)
{
Random rand = new Random();
for (int i = 0; i < 15; i++)
{
for (int j = 0; j < 15; j++)
{
if (board[i, j] != PieceType.Empty)
{
return(new Point(i + 1, j + 1));
}
}
}
return(new Point(7, 7));
}
else
{
BoardOfFIR newBd = new BoardOfFIR();
newBd.boardCopy(this);
Evalute e = getEvalute();
newBd.FindBestMove(-10000, 10000, AIdepth, turn, out move, e);
//ShowInfo(newBd.searchtimes);
}
return(move);
}
Evalute getEvalute()
{
Evalute e = new Evalute();
statistics();
e.judge[0] = this.judge[0];
e.judge[1] = this.judge[1];
return(e);
}
Evalute PointEvaluteChange(Point p, PieceType color)
{
PieceType origin = board[p.X, p.Y];
Evalute e1 = PointEvalute(p);
board[p.X, p.Y] = color;
Evalute e2 = PointEvalute(p);
board[p.X, p.Y] = origin;
return(e2 - e1);
}
Evalute PointEvalute(Point p)
{
Evalute e = new Evalute();
judge[0].init();
judge[1].init();
lineStatistics(new Point(0, p.Y), direction.Horizontal);
lineStatistics(new Point(p.X, 0), direction.Vertical);
int min = Math.Min(p.X, p.Y);
lineStatistics(new Point(p.X - min, p.Y - min), direction.DiagonalUp);
if (p.X + p.Y > 14)
{
lineStatistics(new Point(p.X + p.Y - 14, 14), direction.DiagonalDown);
}
else
{
lineStatistics(new Point(0, p.X + p.Y), direction.DiagonalDown);
}
e.judge[0] = this.judge[0];
e.judge[1] = this.judge[1];
return(e);
}
int FindBestMove(int alpha, int beta, int depth, PieceType color, out Point bestP, Evalute e)//该函数用alphabeta搜索，以在今后搜索更深的深度
{
bestP = new Point(0, 0);
int i, j;
Point tP = new Point();
PieceType oppoColor = oppoPiece(color);
int temp;
Point tempPoint;
Evalute tempE;
int best = -10000;
List <Point> movelist = new List <Point>();//get possible move
for (i = 0; i < 15; i++)
{
for (j = 0; j < 15; j++)
{
tP.X = i; tP.Y = j;
if ((int)board[i, j] >= 2 && isAround(tP) && (board [i, j] != PieceType.Banned || color == PieceType.White))
{
movelist.Add(tP);
}
}
}
if (AIdepth == depth)
{
for (i = 0; i < 15; i++)
{
for (j = 0; j < 15; j++)
{
if (board[i, j] == PieceType.Banned)
{
board[i, j] = PieceType.Empty;
}
}
}
}
if (e.judge[(int)color].H4 + e.judge[(int)color].L4 > 0)
{
for (i = 0; i < 15; i++)
{
for (j = 0; j < 15; j++)
{
tP.X = i; tP.Y = j;
if ((int)board[i, j] >= 2 && checkWin(color, tP) && (board[i, j] != PieceType.Banned || color == PieceType.White))
{
bestP = tP;
return(5000);
}
}
}
}
if (e.judge[(int)oppoColor].L4 > 0)
{
for (i = 0; i < 15; i++)
{
for (j = 0; j < 15; j++)
{
tP.X = i; tP.Y = j;
if ((int)board[i, j] >= 2 && checkWin(oppoColor, tP) && (board[i, j] != PieceType.Banned || oppoColor == PieceType.White))
{
bestP = tP;
return(-5000 + e.getscore(color));
}
}
}
}
if (e.judge[(int)oppoColor].H4 > 0)
{
for (i = 0; i < 15; i++)
{
for (j = 0; j < 15; j++)
{
tP.X = i; tP.Y = j;
if ((int)board[i, j] >= 2 && checkWin(oppoColor, tP) && (board[i, j] != PieceType.Banned || oppoColor == PieceType.White))
{
bestP = tP;
tempE = PointEvaluteChange(tP, color) + e;
if (depth == AIdepth)
{
return(e.getscore(color));
}
setPieceType(tP, color);
temp = -FindBestMove(-beta, -alpha, depth - 1, oppoColor, out tempPoint, tempE);
setPieceType(tP, PieceType.Empty);
return(temp);
}
}
}
}
if (e.judge[(int)color].L3 > 0)
{
for (i = 0; i < 15; i++)
{
for (j = 0; j < 15; j++)
{
tP.X = i; tP.Y = j;
if ((int)board[i, j] >= 2 && isOpenFour(tP, color) && (board[i, j] != PieceType.Banned || oppoColor == PieceType.White))
{
bestP = tP;
return(5000);
}
}
}
}
if (e.judge[(int)color].H3 > 0 && AIdepth <= depth + 1)
{
if (VCF(out tempPoint, color, e))
{
bestP = tempPoint;
return(4000);
}
}
if (depth <= 0)
{
searchtimes++;
return(e.getscore(color));
}
foreach (Point p in movelist)
{
tempE = PointEvaluteChange(p, color) + e;
setPieceType(p, color);
temp = -FindBestMove(-beta, -alpha, depth - 1, oppoColor, out tempPoint, tempE); //tempPoint为下一步最好的走法
setPieceType(p, PieceType.Empty);
if (temp > best) // 找到最佳值
{
best = temp;
if (temp >= beta)// 找到一个Beta走法
{
bestP = p;
break;//提高效率所在
}
if (temp > alpha)
{
bestP = p;
alpha = temp; // '缩小Alpha-Beta边界
}
}
}
if (best < -3000 && depth == AIdepth)//输局已定，选择位置得分最高的点
{
int better = -10000;
foreach (Point p in movelist)
{
temp = PointEvaluteChange(p, oppoColor).getscore(oppoColor);
if (temp > better)
{
better = temp;
bestP = p;
}
}
}
return(best);
}
bool VCF(out Point move, PieceType color, Evalute e)
{
move = new Point(7, 7);
Point tP = new Point();
int i, j;
bool temp;
Point tempP;
Evalute tempE1, tempE2;
PieceType oppoColor = oppoPiece(color);
List <Point> movelist = new List <Point>();
for (i = 0; i < 15; i++)
{
for (j = 0; j < 15; j++)
{
tP.X = i; tP.Y = j;
if (board[i, j] == PieceType.Empty && isFour(tP, color))
{
movelist.Add(tP);
}
}
}
foreach (Point p in movelist)
{
tempE1 = PointEvaluteChange(p, color) + e;
setPieceType(p, color);
for (i = 0; i < 15; i++)
{
for (j = 0; j < 15; j++)
{
tP.X = i; tP.Y = j;
if ((int)board[i, j] >= 2 && checkWin(color, tP))
{
tempE2 = PointEvaluteChange(tP, oppoColor) + tempE1;
if (tempE2.judge[(int)color].H4 > 0)//由于不可能出现活4，只需判断冲4
{
setPieceType(p, PieceType.Empty);
move = p;
return(true);
}
else if (tempE2.judge[(int)oppoColor].L4 + tempE2.judge[(int)oppoColor].H4 > 0)
{
setPieceType(p, PieceType.Empty);
continue;
}
else if (tempE2.judge[(int)color].L3 > 0)
{
move = p;
setPieceType(p, PieceType.Empty);
return(true);
}
else if (tempE2.judge[(int)color].H3 > 0)
{
setPieceType(tP, oppoColor);
temp = VCF(out tempP, color, tempE2);
setPieceType(tP, PieceType.Empty);
if (temp)
{
move = p;
setPieceType(p, PieceType.Empty);
return(true);
}
}
}
}
}
setPieceType(p, PieceType.Empty);
}
return(false);
}