public override CheckersMove NextMove(CheckersGame game)
{
const int minValue = int.MaxValue;
int maxValue = int.MinValue;
CheckersMove bestMove = null;
// Enumerate all moves
foreach (CheckersMove move in game.EnumLegalMoves())
{
if (!game.IsPlaying)
{
break;
}
CheckersGame nextGameState = game.Clone();
nextGameState.MovePiece(move.Clone(nextGameState));
int curValue = minMove(game, nextGameState, 1, maxValue, minValue);
if ((curValue > maxValue) || (bestMove == null))
{
maxValue = curValue;
bestMove = move;
}
OnTick(game);
}
return(bestMove);
}
public override CheckersMove NextMove(CheckersGame game)
{
const int minValue = int.MaxValue;
int maxValue = int.MinValue;
CheckersMove bestMove = null;
// Enumerate all moves
foreach(CheckersMove move in game.EnumLegalMoves())
{
if(!game.IsPlaying)
break;
CheckersGame nextGameState = game.Clone();
nextGameState.MovePiece(move.Clone(nextGameState));
int curValue = minMove(game, nextGameState, 1, maxValue, minValue);
if((curValue > maxValue) || (bestMove == null))
{
maxValue = curValue;
bestMove = move;
}
OnTick(game);
}
return bestMove;
}
int maxMove(CheckersGame initGame, CheckersGame curGame, int depth, int alpha, int beta)
{
// Check algorithm limits..end prematurely, but with an educated approximation
if (doCutOff(initGame, curGame, depth))
{
return(doCalculateStrength(initGame, curGame));
}
// Make move with all possibilities
foreach (CheckersMove move in curGame.EnumLegalMoves())
{
// Create next move
CheckersGame nextGameState = move.Game.Clone();
CheckersMove nextMoveState = move.Clone(nextGameState);
// Make next move and search move space
if (!nextGameState.MovePiece(nextMoveState))
{
continue;
}
int value = minMove(initGame, nextGameState, depth + 1, alpha, beta);
if (value > alpha)
{
// Get new max value
alpha = value;
}
if (alpha > beta)
{
// Return max value with pruning
return(beta);
}
}
// Return alpha (max value)
return(alpha);
}
int minMove(CheckersGame initGame, CheckersGame curGame, int depth, int alpha, int beta)
{
// Check algorithm limits..end prematurely, but with an educated approximation
if(doCutOff(initGame, curGame, depth))
return -doCalculateStrength(initGame, curGame);
// Make move with all possibilities
foreach(CheckersMove move in curGame.EnumLegalMoves())
{
// Create next move
CheckersGame nextGameState = move.Game.Clone();
CheckersMove nextMoveState = move.Clone(nextGameState);
// Make next move and search move space
if(!nextGameState.MovePiece(nextMoveState))
continue;
int value = maxMove(initGame, nextGameState, depth + 1, alpha, beta);
if(value < beta)
{
// Get new min value
beta = value;
}
if(beta < alpha)
{
// Return min value with pruning
return alpha;
}
}
// Return alpha (max value)
return beta;
}
