public int findBestMove(Node currentNode, int best) {
int turn = currentNode.getBoard().CurrentPlayer();
// set the current value of the current node to compare with children node
if (turn != player) currentNode.setValue(Float.POSITIVE_INFINITY);
else currentNode.setValue(Float.NEGATIVE_INFINITY);
// Check each pit on your side to find the best move. */
for (int i = 0; i < 6; i++)
if (currentNode.getBoard().validMove(i)) {
try {
MancalaGameState newBoard = currentNode.getBoard().copy();
try {
newBoard.play(i);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Node newNode = new Node(newBoard, currentNode.getDepth() + 1);
newNode.setParent(currentNode);
currentNode.setChild(newNode, i);
// CUT OFF
if (newNode.getBoard().checkEndGame() || (newNode.getDepth() >= cutoffDepth)) {
RegressionState aState = new RegressionState(newNode.getBoard(), player);
newNode.setValue(predictedValue(aState, weight));
} else findBestMove(newNode, best);
// alpha-beta pruning
// AI = MAX
// pick the child with larger value
if (currentNode.getBoard().CurrentPlayer() == player) {
if (currentNode.getChild(i) != null) {
if (currentNode.getChild(i).getValue() > currentNode.getValue()) {
currentNode.setValue(currentNode.getChild(i).getValue());
best = i;
}
}
currentNode.deleteChild(i);
// alpha cut off if our value is greater than ANY
// player/MIN parent value
Node nodePtr = currentNode;
while (nodePtr.getParent() != null) {
nodePtr = nodePtr.getParent();
if ((nodePtr.getBoard().CurrentPlayer != player)
&& (currentNode.getValue() > nodePtr.getValue())) {
nodePtr = null;
return best;
}
}
nodePtr = null;
}
// Player = MIN
// pick the child with smaller value
if (currentNode.getBoard().CurrentPlayer() != player) {
if (currentNode.getChild(i) != null) {
if (currentNode.getChild(i).getValue() < currentNode.getValue()) {
currentNode.setValue(currentNode.getChild(i).getValue());
best = i;
}
}
currentNode.deleteChild(i);
// beta cut off if our value is less than ANY
// computer/MAX parent value
Node nodePtr = currentNode;
while (nodePtr.getParent() != null) {
nodePtr = nodePtr.getParent();
if ((nodePtr.getBoard().CurrentPlayer() == player)
&& (currentNode.getValue() < nodePtr.getValue())) {
nodePtr = null;
return best;
}
}
nodePtr = null;
}
} catch (java.lang.OutOfMemoryError e) {
System.out.println("OUT OF MEM");
return -1;
}
}
return best; // return the best move
}
public void updateHistory(MancalaGameState gs) {
RegressionState aState = new RegressionState(gs.copy(), player);
gameHistory.add(aState);
}