private double tryMove( int[,] board, Move move) {
double []input = new double[9];
int index = 0;
for (int x = 0; x < 3; x++) {
for (int y = 0; y < 3; y++) {
if (board[x,y] == TicTacToe.NOUGHTS) {
input[index] = -1;
} else if (board[x,y] == TicTacToe.CROSSES) {
input[index] = 1;
} else if (board[x,y] == TicTacToe.EMPTY) {
input[index] = 0;
}
if ((x == move.x) && (y == move.y)) {
input[index] = -1;
}
index++;
}
}
double []output = this.network.ComputeOutputs(input);
return output[0];
}
private Move centerOpen( int[,] board, int color) {
Move center = new Move((int) 1, (int) 1, color);
if (Board.isEmpty(board, center)) {
return center;
} else {
return null;
}
}
/**
* Gets this player's next move. It is always the next available square.
*
* @param board
* <code>Board</code> representation of the current game state.
* @param prev
* <code>Move</code> representing the previous move in the the
* game.
* @param player
* <code>int</code> representing the pieces this
* <code>Player</code> is playing with. One of
* <code>TicTacToe.NOUGHTS</code> or
* <code>TicTacToe.CROSSES</code>
* @return <code>Move</code> Next move for this player.
*/
public Move getMove( int[,] board, Move prev, int player) {
for (byte x = 0; x < 3; x++) {
for (byte y = 0; y < 3; y++) {
Move m = new Move(x, y, player);
if (Board.isEmpty(board, m)) {
return m;
}
}
}
throw new Exception("I'm just looking for the first "
+ "empty square and I can't move!");
}
/**
* Gets the next move of this player.
*
* @param board
* <code>Board</code> representation of the current game state.
* @param prev
* <code>Move</code> representing the previous move in the the
* game.
* @param color
* <code>int</code> representing the pieces this
* <code>Player</code> is playing with. One of
* <code>TicTacToe.NOUGHTS</code> or
* <code>TicTacToe.CROSSES</code>
* @return <code>Move</code> Next move of this player.
*/
public Move getMove( int[,] board, Move prev, int color) {
Board.printBoard(board);
// ask for move
Console.WriteLine("You are playing: " + TicTacToe.resolvePiece(color)
+ ", select your move.");
Console.Write("X position? ");
int x = getCoord();
Console.Write("Y position? ");
int y = getCoord();
return new Move(x, y, color);
}
/**
* Gets this player's next move. It is always the next available square.
*
* @param board
* <code>Board</code> representation of the current game state.
* @param prev
* <code>Move</code> representing the previous move in the the
* game.
* @param player
* <code>int</code> representing the pieces this
* <code>Player</code> is playing with. One of
* <code>TicTacToe.NOUGHTS</code> or
* <code>TicTacToe.CROSSES</code>
* @return <code>Move</code> Next move for this player.
*/
public Move getMove( int[,] board, Move prev, int player) {
Random rand = new Random();
for (;;) {
int x = (int) (rand.NextDouble() * 3.0);
int y = (int)(rand.NextDouble() * 3.0);
Move m = new Move(x, y, player);
if (Board.isEmpty(board, m)) {
return m;
}
}
}
private Move findWin( int[,] board, Move move1,
Move move2, Move move3, int color) {
if ((board[move1.x,move1.y] == color)
&& (board[move2.x,move2.y] == color)
&& (board[move3.x,move3.y] == TicTacToe.EMPTY)) {
return move3;
} else if ((board[move2.x,move2.y] == color)
&& (board[move3.x,move3.y] == color)
&& (board[move1.x,move1.y] == TicTacToe.EMPTY)) {
return move1;
} else if ((board[move1.x,move1.y] == color)
&& (board[move3.x,move3.y] == color)
&& (board[move2.x,move2.y] == TicTacToe.EMPTY)) {
return move2;
} else {
return null;
}
}
private Move cornerOpen( int[,] board, int color) {
Move corner1 = new Move((int) 0, (int) 0, color);
Move corner2 = new Move((int) 2, (int) 2, color);
Move corner3 = new Move((int) 2, (int) 0, color);
Move corner4 = new Move((int) 0, (int) 2, color);
if (Board.isEmpty(board, corner1)) {
return corner1;
} else if (Board.isEmpty(board, corner2)) {
return corner2;
} else if (Board.isEmpty(board, corner3)) {
return corner3;
} else if (Board.isEmpty(board, corner4)) {
return corner4;
} else {
return null;
}
}
public Move getMove( int[,] board, Move prev, int color) {
Move bestMove = null;
double bestScore = double.MinValue;
for (int x = 0; x <3; x++) {
for (int y = 0; y < 3; y++) {
Move move = new Move((int) x, (int) y, color);
if (Board.isEmpty(board, move)) {
double d = tryMove(board, move);
if ((d > bestScore) || (bestMove == null)) {
bestScore = d;
bestMove = move;
}
}
}
}
return bestMove;
}
public static Move[] GetEmptyPositions(int[,] board, int visual)
{
int length = board.Length, actualSize = 0;
Move[] emptyPositions = new Move[] { };
Array.Resize(ref emptyPositions, length);
for (int x = 0; x < 3; x++)
{
for (int y = 0; y < 3; y++)
{
if (board[x, y] == TicTacToe.EMPTY)
{
emptyPositions[actualSize] = new Move(x, y, visual);
actualSize++;
}
}
}
Array.Resize(ref emptyPositions, actualSize);
return emptyPositions;
}
private Move canWin( int [,]board, int color) {
Move move1, move2, move3, move;
for (int i = 0; i < 3; i++) {
move1 = new Move((int) 0, (int) i, color);
move2 = new Move((int) 1, (int) i, color);
move3 = new Move((int) 2, (int) i, color);
move = findWin(board, move1, move2, move3, color);
if (move != null) {
return move;
}
}
for (int i = 0; i < 3; i++) {
move1 = new Move((int) i, (int) 0, color);
move2 = new Move((int) i, (int) 1, color);
move3 = new Move((int) i, (int) 2, color);
move = findWin(board, move1, move2, move3, color);
if (move != null) {
return move;
}
}
move1 = new Move((int) 0, (int) 0, color);
move2 = new Move((int) 1, (int) 1, color);
move3 = new Move((int) 2, (int) 2, color);
move = findWin(board, move1, move2, move3, color);
if (move != null) {
return move;
}
move1 = new Move((int) 2, (int) 0, color);
move2 = new Move((int) 0, (int) 0, color);
move3 = new Move((int) 0, (int) 2, color);
move = findWin(board, move1, move2, move3, color);
if (move != null) {
return move;
}
return null;
}
// main guts of the game
private Player play(Move prev) {
for (;;) {
// new board here else players can alter the game board as they
// wish!
int[,] b = Board.copy(this._board);
Move move = this._players[this._player].getMove(b, prev,
this._player);
if (move == null) {
throw new Exception("Player supplied null move");
}
// check square is empty
if (!Board.isEmpty(this._board, move)) {
Console.WriteLine("That square is not empty");
play(prev);
}
// place piece
if (!Board.placePiece(this._board, move)) {
Console.WriteLine("Illegal Move - try again");
play(prev);
}
if (Board.isWinner(this._board, this._player)) {
return this._players[this._player];
}
// change player
this._player = TicTacToe.reverse(this._player);
if (Board.isFull(this._board)) {
return null;
}
prev = move;
}
}
/**
* Gets the next move of this player.
*
* @param board
* <code>Board</code> representation of the current game state.
* @param prev
* <code>Move</code> representing the previous move in the the
* game.
* @param color
* <code>int</code> representing the pieces this
* <code>Player</code> is playing with. One of
* <code>TicTacToe.NOUGHTS</code> or
* <code>TicTacToe.CROSSES</code>
* @return <code>Move</code> Next move of this player.
*/
public Move getMove( int[,] board, Move prev, int color) {
this._player = color;
Node root = new Node(board, prev);
int max = int.MinValue;
Node child;
Node bestNode = null;
while ((child = root.getChild()) != null) {
int val = minimaxAB(child, true, int.MinValue,
int.MaxValue);
if (val >= max) {
max = val;
bestNode = child;
}
}
return bestNode.move();
}
public Move getMove( int[,] board, Move prev, int color) {
if (Board.isFull(board)) {
return null;
}
Move result = null;
int other = TicTacToe.reverse(color);
if (result == null) {
result = canWin(board, color);
}
if (result == null) {
result = canWin(board, other);
}
// Step 1: Is the center open
if (result == null) {
result = centerOpen(board, color);
}
// Step 2: Is the corner open
if (result == null) {
result = cornerOpen(board, color);
}
// Step 3: Move somewhere
if (result == null) {
result = moveSomewhere(board, color);
}
if (result.color() != color) {
result = new Move(result.x, result.y, color);
}
return result;
}
/**
* Determines if the square the specified <code>Move</code> takes place in
* is empty or not.
*
* @param move
* <code>Move</code> to check position of.
* @return <code>bool</code>, true if the square is empty.
*/
public static bool isEmpty( int[,] board, Move move) {
return (board[move.x,move.y] == TicTacToe.EMPTY);
}
/**
* Does the move specified in <code>m</code> on <code>board</code>.
*
* @param board
* <code>int[,]</code> of board to perform move on.
* @param m
* <code>Move</code> to perform.
* @return <code>bool</code> of whether the move succeeded or not.
* @throws IllegalStateException
* If the move is not legal.
*/
public static bool placePiece( int[,] board, Move m) {
if (board[m.x,m.y] != TicTacToe.EMPTY) {
throw new Exception("Tried to play a piece on "
+ "top of another at (" + m.x + ", " + m.y + ")");
} else {
board[m.x,m.y] = m.color();
return true;
}
}
/**
* Creates a node with the specified board position, reached by the
* specified move.
*
* @param board
* <code>Board</code> of the board position of this node.
* @param move
* <code>Move</code> last move that was taken to reach this
* board position.
*/
public Node( int[,] board, Move move) {
this._board = board;
this._move = move;
}
/**
* Gets the "next" child for this node, or <code>null</code> if all
* children of this node have already been found.
*
* @return <code>Node</code> Representation of child (one move on) in the
* game tree.
*/
public Node getChild() {
bool firstColumn = true;
for (int x = this._x; x < 3; x++) {
int starter = 0;
if (firstColumn) {
starter = this._y;
}
for (int y = starter; y < 3; y++) {
Move m = new Move(x, y, this.player());
if (Board.isEmpty(this._board, m)) {
int[,] newPos = Board.copy(this._board);
Board.placePiece(newPos, m);
Node child = new Node(newPos, m);
this._children[this.childNum++] = child;
if (y >= (3 - 1)) {
this._x = (int) (x + 1);
this._y = 0;
} else {
this._x = x;
this._y = (int) (y + 1);
}
this._leaf = false;
this._leafdef = true;
return child;
}
}
firstColumn = false;
}
this._leaf = true;
this._leafdef = true;
return null;
}
