/*
* Play one Kalah game with the two given players, with firstPlayer
* starting. This function returns TOP's score.
*/
public static int playGame(Player pTop, Player pBot, Position firstPlayer)
{
b = new Board(firstPlayer);
if (firstPlayer == Position.Top)
{
Console.WriteLine("Player " + pTop.getName() + " starts.");
}
else
{
Console.WriteLine("Player " + pBot.getName() + " starts.");
}
b.display();
while (!b.gameOver())
{
Console.WriteLine();
if (b.whoseMove() == Position.Top)
{
move = pTop.chooseMove(b);
Console.WriteLine(pTop.getName() + " chooses move " + move);
}
else
{
move = pBot.chooseMove(b);
Console.WriteLine(pBot.getName() + " chooses move " + move);
}
b.makeMove(move, true); // last parameter says to be chatty
b.display();
if (b.gameOver())
{
if (b.winner() == Position.Top)
{
Console.WriteLine("Player " + pTop.getName() +
" (TOP) wins " + b.scoreTop() + " to " + b.scoreBot());
}
else if (b.winner() == Position.Bottom)
{
Console.WriteLine("Player " + pBot.getName() +
" (BOTTOM) wins " + b.scoreBot() + " to " + b.scoreTop());
}
else
{
Console.WriteLine("A tie!");
}
}
else
if (b.whoseMove() == Position.Top)
{
Console.WriteLine(pTop.getName() + " to move.");
}
else
{
Console.WriteLine(pBot.getName() + " to move.");
}
}
return(b.scoreTop());
}
/* minimaxVal with Alpha-Beta Pruning
* returns evaluation if it reaches maxDepth, else calculates min or max if it is opponent's turn or my turn respectively
*
*/
public DataWrapper minimaxVal(Board b, int d, int alpha, int beta)
{
//when time runs out, this evaluates to true
//when the cancelled execption is thrown, the last best move will be returned in the chooseMove() try->catch statement
if (cancellationToken.IsCancellationRequested)
{
throw new OperationCanceledException();
}
//return if reached gameover or max depth
if (b.gameOver() || d == 0)
{
return(new DataWrapper(0, evaluate(b), 0, 0));
}
DataWrapper data;
//look through right positions for moves
int start = 0;
int end = 5;
if (b.whoseMove() == Position.Top)
{
start = 7;
end = 12;
}
//initialize variables
int bestMove = -1;
int secondBestMove = -1;
int bestValue = int.MinValue;
int secondBestValue = int.MinValue;
//loop through all possible moves
for (int move = start; move <= end; move++)
{
//if it is a legal move, check the value of it
if (b.legalMove(move))
{
//create copy of board, make move, and evaluate it by recursing
Board newBoard = new Board(b);
newBoard.makeMove(move, false);
data = minimaxVal(newBoard, d - 1, alpha, beta);
//if value, move pair is best or worst, set bestValue and bestMove to it
//also set second best value, move pair to previous value
if (isBetterMove(b.whoseMove(), bestValue, data.getValue(), d))
{
secondBestValue = bestValue;
bestValue = data.getValue();
secondBestMove = bestMove;
bestMove = move;
//alpha beta pruning
if (b.whoseMove() == this.position)
{
alpha = Math.Max(alpha, bestValue);
}
else
{
beta = Math.Min(beta, bestValue);
}
}
//if alpha is greater than or equal to beta, we can skip other moves (pruning part of alpha beta pruning)
if (alpha >= beta)
{
break;
}
}
}
//return move pairs
return(new DataWrapper(bestMove, bestValue, secondBestMove, secondBestValue));
}
//Minimax function. Note that the Max is for the bottom play, It just made more sense to me that way. returns best score and best move.
private int[] prunedminimax(Board b, int depth, Stopwatch timer, int lastbestscore, Position lastplayer, int playsinarow)
{
int[] value = new int[2];
int bestscore;
if (b.whoseMove() == Position.Top) //set the infinity max or infinity min depending on whose turn it is.
{
bestscore = 1111111;
}
else
{
bestscore = -1111111;
}
int bestmove = -1; //returns this number if DFS doesnt finish
int[] tempvalue = new int[2]; //temporary value that will be used to find the best score and value
if ((depth > 0 && !b.gameOver())) //as long as game isnt over, or you reached the depth
{
bool firstturn = true; //used to keep track of the first turn
for (int i = 0; i < 6; i++)
{
if (b.whoseMove() == Position.Top)
{
if (b.legalMove(i + 7))
{
Board currentBoard = new Board(b);
currentBoard.makeMove(i + 7, false);
if (lastplayer == Position.Top)//this is used to keep track of who has had the most turns
{
tempvalue = prunedminimax(currentBoard, depth - 1, timer, bestscore, Position.Top, playsinarow - 1);
}
else
{
tempvalue = prunedminimax(currentBoard, depth - 1, timer, bestscore, Position.Top, playsinarow);
}
if (firstturn)
{
bestscore = tempvalue[0];
bestmove = i + 7;
firstturn = false;//no longer first turn so set to false
}
//for non-first turns, check to see if tempvalue is lower then best score.
else if (tempvalue[0] < bestscore)
{
bestscore = tempvalue[0];
bestmove = i + 7;
}
if ((lastplayer == Position.Bottom) && (bestscore < lastbestscore))
{
break; //prunes the branches if necesary.
}
}
}
else
{
if (b.legalMove(i))
{
Board currentBoard = new Board(b);
currentBoard.makeMove(i, false);
if (lastplayer == Position.Bottom)
{
tempvalue = prunedminimax(currentBoard, depth - 1, timer, bestscore, Position.Bottom, playsinarow + 1);
}
else
{
tempvalue = prunedminimax(currentBoard, depth - 1, timer, bestscore, Position.Bottom, playsinarow);
}
if (firstturn)
{
bestscore = tempvalue[0];
bestmove = i;
firstturn = false;
}
else if (tempvalue[0] > bestscore)
{
bestscore = tempvalue[0];
bestmove = i;
}
if ((lastplayer == Position.Top) && (bestscore > lastbestscore))
{
break;
}
}
}
if (!(timer.ElapsedMilliseconds < getTimePerMove() - 10))//if there are only 10 ms till the turn is up, return -1 for the best move
{
value[1] = -1;
return(value);
}
}
}
else //reaches this if it is a node.
{
bestscore = evaluate(b, playsinarow);
}
value[0] = bestscore;
value[1] = bestmove;
return(value);
}
//int d is depth of miniMax search. int max should be 1 for getting the max result, -1 for min. Should return moveResult object
public moveResult miniMax(Board b, int d, double timeLimit, int max, Timer timer)
{
//Set up variables
int bestVal = int.MinValue;
int bestMove = 0;
moveResult bestMR = new moveResult(bestMove, bestVal);
//Base case: depth is 0, time is up or game is over. Returns a moveResult with the best score value and 0 move value
if (d == 0 || timeOut || b.gameOver())
{
bestVal = evaluate(b);
//Console.WriteLine("Best score found to be " + bestVal);
moveResult bestMoveResult = new moveResult(bestMove, bestVal);
return(bestMoveResult);
}
if (b.whoseMove() == Position.Top)
{
for (int move = 7; move <= 12; move++)
{
//Console.WriteLine("");
//Recurse if the move is legal, time hasn't expired and game isn't over
int val = 0;
if (b.legalMove(move) && !timeOut && !b.gameOver())
{
Board b1 = new Board(b);
b1.makeMove(move, true);
int newDepth = d - 1;
//Switch the value of max to be the opposite for the recursion
int mnOrMx = max * -1;
//Console.WriteLine("Recursing from " + d + " to " + newDepth + "...");
val = miniMax(b1, newDepth, timeLimit, mnOrMx, timer).getScore();
//If at "max" level, prioritize and return maximum value
if (max == 1)
{
//If there's a new max, update bestValue and bestMove
if (val > bestVal)
{
bestVal = val;
bestMove = move;
}
}
//If at "min" level, prioritize and return minimum value
if (max == -1)
{
//If there's a new min, update bestValue and bestMove
if (val < bestVal || val != int.MinValue)
{
bestVal = val;
bestMove = move;
}
}
}
}
bestMR = new moveResult(bestMove, bestVal);
return(bestMR);
}
else
{
for (int move = 0; move <= 5; move++)
{
//Console.WriteLine("");
//Recurse if the move is legal, time hasn't expired and game isn't over
if (b.legalMove(move) && !timeOut && !b.gameOver())
{
Board b1 = new Board(b);
b1.makeMove(move, true);
int newDepth = d - 1;
//Switch the value of max to be the opposite for the recursion
int mnOrMx = max * -1;
// Console.WriteLine("Recursing from " + d + " to " + newDepth + "...");
int val = miniMax(b1, newDepth, timeLimit, mnOrMx, timer).getScore();
// Console.WriteLine("New Value: " + val);
//If at "max" level, prioritize and return maximum value
if (max == 1)
{
//If there's a new max, update bestValue and bestMove
if (val > bestVal)
{
bestVal = val;
bestMove = move;
}
}
//If at "min" level, prioritize and return minimum value
if (max == -1)
{
//If there's a new min, update bestValue and bestMove
if (val < bestVal || val != int.MinValue)
{
bestVal = val;
bestMove = move;
}
}
}
}
bestMR = new moveResult(bestMove, bestVal);
return(bestMR);
}
//Console.WriteLine("Best move: " + bestMove + " Best score: " + bestVal);
bestMR = new moveResult(bestMove, bestVal);
return(bestMR);
}
private Result minimaxVal(Board b, int d, Stopwatch w, int alpha, int beta)
{
if (w.ElapsedMilliseconds > getTimePerMove())
{
throw new MoveTimedOutException();
}
int bestMove = 0;
int bestVal;
bool gameCompleted = false;
if (b.gameOver() || d == 0)
{
return(new Result(0, evaluate(b), b.gameOver()));
}
if (b.whoseMove() == Position.Top)
{
bestVal = Int32.MinValue;
for (int move = 7; move <= 12; move++)
{
if (b.legalMove(move))
{
Board b1 = new Board(b);
b1.makeMove(move, false);
Result val = minimaxVal(b1, d - 1, w, alpha, beta);
if (val.getScore() > bestVal)
{
bestVal = val.getScore();
bestMove = move;
gameCompleted = val.isEndGame();
}
if (bestVal > alpha)
{
alpha = bestVal;
}
}
}
}
else
{
bestVal = Int32.MaxValue;
for (int move = 0; move <= 5; move++)
{
if (b.legalMove(move))
{
Board b1 = new Board(b);
b1.makeMove(move, false);
Result val = minimaxVal(b1, d - 1, w, alpha, beta);
if (val.getScore() < bestVal)
{
bestVal = val.getScore();
bestMove = move;
gameCompleted = val.isEndGame();
}
if (bestVal < beta)
{
beta = bestVal;
}
}
}
}
return(new Result(bestMove, bestVal, gameCompleted));
}