001 /*
002 * Created on Feb 15, 2005
003 *
004 */
005 package aima.games;
006
007 import java.util.ArrayList;
008
009 import aima.basic.XYLocation;
010
011 /**
012 * @author Ravi Mohan
013 *
014 */
015 public class TicTacToe extends Game {
016 public TicTacToe() {
017 ArrayList<XYLocation> moves = new ArrayList<XYLocation>();
018 for (int i = 0; i < 3; i++) {
019 for (int j = 0; j < 3; j++) {
020 XYLocation loc = new XYLocation(i, j);
021 moves.add(loc);
022 }
023 }
024 initialState.put("moves", moves);
025 initialState.put("player", "X");
026 initialState.put("utility", new Integer(0));
027 initialState.put("board", new TicTacToeBoard());
028 initialState.put("level", new Integer(0));
029 presentState = initialState;
030 }
031
032 public TicTacToeBoard getBoard(GameState state) {
033
034 return (TicTacToeBoard) state.get("board");
035 }
036
037 @Override
038 public ArrayList getSuccessorStates(GameState state) {
039 GameState temp = presentState;
040 ArrayList<Object> retVal = new ArrayList<Object>();
041 int parentLevel = getLevel(state);
042 for (int i = 0; i < getMoves(state).size(); i++) {
043 XYLocation loc = (XYLocation) getMoves(state).get(i);
044
045 GameState aState = makeMove(state, loc);
046 aState.put("moveMade", loc);
047 aState.put("level", new Integer(parentLevel + 1));
048 retVal.add(aState);
049
050 }
051 presentState = temp;
052 return retVal;
053 }
054
055 @Override
056 public GameState makeMove(GameState state, Object o) {
057 XYLocation loc = (XYLocation) o;
058 return makeMove(state, loc.getXCoOrdinate(), loc.getYCoOrdinate());
059 }
060
061 public GameState makeMove(GameState state, int x, int y) {
062 GameState temp = getMove(state, x, y);
063 if (temp != null) {
064 presentState = temp;
065 }
066 return presentState;
067 }
068
069 public GameState makeMove(int x, int y) {
070 GameState state = presentState;
071 GameState temp = getMove(state, x, y);
072 if (temp != null) {
073 presentState = temp;
074 }
075 return presentState;
076 }
077
078 public GameState getMove(GameState state, int x, int y) {
079 GameState retVal = null;
080 XYLocation loc = new XYLocation(x, y);
081 ArrayList moves = getMoves(state);
082 ArrayList newMoves = (ArrayList) moves.clone();
083 if (moves.contains(loc)) {
084 int index = newMoves.indexOf(loc);
085 newMoves.remove(index);
086
087 retVal = new GameState();
088
089 retVal.put("moves", newMoves);
090 TicTacToeBoard newBoard = getBoard(state).cloneBoard();
091 if (getPlayerToMove(state) == "X") {
092 newBoard.markX(x, y);
093 retVal.put("player", "O");
094
095 } else {
096 newBoard.markO(x, y);
097 retVal.put("player", "X");
098
099 }
100 retVal.put("board", newBoard);
101 retVal.put("utility", new Integer(computeUtility(newBoard,
102 getPlayerToMove(getState()))));
103 retVal.put("level", new Integer(getLevel(state) + 1));
104 // presentState = retVal;
105 }
106 return retVal;
107 }
108
109 @Override
110 public int computeUtility(GameState state) {
111 int utility = computeUtility((TicTacToeBoard) state.get("board"),
112 (getPlayerToMove(state)));
113 return utility;
114 }
115
116 private int computeUtility(TicTacToeBoard aBoard, String playerToMove) {
117 int retVal = 0;
118 if (aBoard.lineThroughBoard()) {
119 if (playerToMove.equals("X")) {
120 retVal = -1;
121 } else {
122 retVal = 1;
123 }
124
125 }
126 return retVal;
127 }
128
129 @Override
130 public boolean terminalTest(GameState state) {
131 TicTacToeBoard board = (TicTacToeBoard) state.get("board");
132 boolean line = board.lineThroughBoard();
133 boolean filled = board.getNumberOfMarkedPositions() == 9;
134 return (line || filled);
135 }
136
137 public void printPossibleMoves() {
138 System.out.println("Possible moves");
139
140 ArrayList moves = getMoves(presentState);
141 for (int i = 0; i < moves.size(); i++) {
142 XYLocation moveLoc = (XYLocation) moves.get(i);
143 GameState newState = getMove(presentState,
144 moveLoc.getXCoOrdinate(), moveLoc.getYCoOrdinate());
145 TicTacToeBoard board = (TicTacToeBoard) newState.get("board");
146 System.out.println("utility = " + computeUtility(newState));
147 System.out.println("");
148 }
149
150 }
151
152 @Override
153 public int getMiniMaxValue(GameState state) {
154 // statesSeen = new ArrayList();
155 // System.out.println("In get Minimax Value");
156 // System.out.println("Received state ");
157 // ((TicTacToeBoard)state.get("board")).print();
158 if (getPlayerToMove(state).equalsIgnoreCase("X")) {
159 return maxValue(state);
160
161 } else {
162 return minValue(state);
163 }
164 }
165
166 @Override
167 public int getAlphaBetaValue(GameState state) {
168
169 if (getPlayerToMove(state).equalsIgnoreCase("X")) {
170 AlphaBeta initial = new AlphaBeta(Integer.MIN_VALUE,
171 Integer.MAX_VALUE);
172 int max = maxValue(state, initial);
173 return max;
174
175 } else {
176 // invert?
177 AlphaBeta initial = new AlphaBeta(Integer.MIN_VALUE,
178 Integer.MAX_VALUE);
179 return minValue(state, initial);
180 }
181 }
182 }