• Source 
    1. package tictac;
    2.  
    3.  
    4. import java.util.*;
    5.  
    6. public class Strategy1 {
    7.  
    8. 	int bestScore;
    9. 	int score;
    10. 	int bestMove;
    11. 	int depth;
    12. 	ArrayList<Integer> myMoves = new ArrayList<Integer>();
    13. 	//Player imitateHuman = new HumanPlayer("HUMAN",'O');
    14. 	//Player AI = new HumanPlayer("AI",'X');
    15.  
    16. 	public void displayMoves()
    17. 	{
    18. 		for(int i = 0; i < myMoves.size();i++)
    19. 		{
    20. 			System.out.println(myMoves.get(i) + " ");
    21. 		}
    22. 	}
    23. 	public void makeMove(Player p, Cell c)
    24. 	{
    25. 		c.setSymbol(p.getSymbol());
    26. 	}
    27. 	public void unmakeMove(Cell c)
    28. 	{
    29. 		c.setSymbol('.');
    30. 	}
    31. 	ArrayList<Integer> generateMoves(Board b)
    32. 	{
    33. 		ArrayList<Integer> allPossibleMoves = new ArrayList<Integer>(); 
    34. 		for(int i = 0; i < b.myBoard.size();i++)
    35. 		{
    36. 			if(b.myBoard.get(i).getSymbol() == '.')
    37. 			{
    38. 				allPossibleMoves.add(i);
    39. 			}
    40. 		}
    41. 		return allPossibleMoves;
    42. 	}
    43. 	int evaluate(Board b)
    44. 	{
    45. 		if(GameController.hasWon(b.whoseTurn, b))
    46. 		{	
    47. 			//if(p1.getId()=="AI")
    48. 				return 100 - depth;
    49. 			//else
    50. 				//return depth - 100;
    51. 		}
    52.  
    53. 		if(GameController.hasWon(b.whoseNotInTurn,b))
    54. 		{
    55. 			//if(p2.getId()=="AI")
    56. 				//return 100 - depth;
    57. 			//else
    58. 				return depth - 100;
    59. 		}	
    60.  
    61. 		return 0;	
    62. 	}
    63. 	void swapPlayers(Board b)
    64. 	{
    65. 		Player temp;
    66. 		temp = b.getWhoseTurn();
    67. 		b.setWhoseTurn(b.getWhoseNotInTurn());
    68. 		b.setWhoseNotInTurn(temp);
    69.  
    70. 	}
    71. 	public  int minimax(Board b) //player1 is AI
    72. 	{
    73. 		//depth+=10;
    74. 	   System.out.println("Current board is  " );
    75. 		System.out.println("To play now on this board is  " + b.whoseTurn.getId() );
    76. 		b.display();
    77. 		if( (GameController.hasWon(b.whoseTurn,b)) || (GameController.hasWon(b.whoseNotInTurn, b)) || (GameController.isDraw(b.whoseTurn,b,b.whoseNotInTurn)))
    78. 		{
    79.  
    80. 				return evaluate(b);		
    81. 		}
    82. 		ArrayList<Integer> possibleMoves = generateMoves(b);
    83.  
    84. 		if(b.whoseTurn.getId()=="AI")
    85. 		{
    86.  
    87. 			 bestScore = -1000000;
    88.  
    89. 			for(int i = 0; i < possibleMoves.size();i++)
    90. 			{
    91. 				int move = possibleMoves.get(i);
    92. 				b.myBoard.get(move).setSymbol(b.whoseTurn.getSymbol());
    93.  
    94. 				swapPlayers(b);
    95. 				score = minimax (b);		
    96.  
    97. 				if(score > bestScore)
    98. 				{
    99.  
    100. 					bestScore = score;
    101. 					bestMove = move;
    102. 					System.out.println("In maximum Move is " + move + "BESTScore is" + score);
    103.  
    104. 				}
    105. 				unmakeMove(b.myBoard.get(move));
    106.  
    107. 			}
    108.  
    109. 			return bestMove;
    110. 		}
    111. 		else
    112. 		{
    113. 				bestScore = 1000000;
    114. 			for(int i = 0; i < possibleMoves.size();i++)
    115. 			{
    116. 				int move = possibleMoves.get(i);
    117. 				b.myBoard.get(move).setSymbol(b.whoseTurn.getSymbol());
    118.  
    119. 				swapPlayers(b);
    120. 				score = minimax(b);
    121.  
    122. 				if(score < bestScore)
    123. 				{
    124. 					myMoves.add(move);
    125. 					bestScore = score;
    126. 					bestMove = move;
    127. 					System.out.println("In minimum Move is " + move + "Score is" + score);
    128.  
    129. 				}
    130. 				unmakeMove(b.myBoard.get(move));
    131.  
    132. 			}
    133. 			return bestMove;
    134.  
    135.  
    136.  
    137. 		}
    138.  
    139.  
    140.  
    141.  
    142. 	}
    143. 	public static void main(String[] args)
    144. 	{
    145.  
    146. 		Player AI = new HumanPlayer("AI",'X');
    147. 		Player Human = new HumanPlayer("Human",'O');
    148. 		Board testBoard = new Board();
    149. 		testBoard.setWhoseTurn(AI);
    150. 		testBoard.setWhoseNotInTurn(Human);
    151. 		testBoard.myBoard.get(3).setSymbol(AI.getSymbol());
    152. 		testBoard.myBoard.get(6).setSymbol(AI.getSymbol());
    153. 		testBoard.myBoard.get(7).setSymbol('O');
    154. 		testBoard.myBoard.get(8).setSymbol('O');
    155. 		testBoard.myBoard.get(0).setSymbol('O');
    156. 		testBoard.myBoard.get(2).setSymbol(AI.getSymbol());
    157. 		//testBoard.myBoard.get(8).setSymbol(AI.getSymbol());
    158. 		Strategy1 instance = new Strategy1();
    159. 		int score = instance.minimax(testBoard);
    160. 		System.out.println("Move " + score);
    161. 		//testBoard.display();	
    162. 		//instance.displayMoves();
    163.  
    164.  
    165. 	}
    166.  
    167.  
    168. }
    169.