/** Returns a move that minimizes the maximum utility by this agent. */
private Move min(Board board, int depth) {
nodes++;
// If the node is a terminal, return the heuristic, which is the score advantage for this agent.
if (depth <= 0) return new Move(board.getScoreAdvantage(ID));
// Get an array of all legal moves, and test all of them to find the one that maximizes the
// minimum
// score advantage of this agent.
Move[] moves = board.getLegalMoves();
// If there are no legal moves, return a value reflective of whether the agent has won, tied, or
// lost.
if (moves.length == 0)
return new Move(
(board.getScoreAdvantage(ID) > 0)
? Integer.MAX_VALUE
: ((board.getScoreAdvantage(ID) == 0) ? 0 : Integer.MIN_VALUE));
Move min = null;
for (Move m : moves) {
// Test the given move and replace min with the move if it has a lower value.
Move test = max(m.move(board), depth - 1);
board.unmove(1);
if (min == null || test.getValue() < min.getValue()) {
min = m;
min.setValue(test.getValue());
}
}
// Return the minimum move
return min;
}
