我正在制作一个用于练习制作课程的tictactoe板，我遇到了算法问题。它似乎是回归最好的进攻，但它没有发挥防守。我不知道我搞砸了哪里，似乎无法找到它。我已经在这里查看了很多关于它的事情，并将它与类似的项目进行了比较，但似乎仍然无法得到它。这是我的代码。
package TicTacToe;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.Scanner;
public class Solution {
private static GameBoard currentBoard;
private static Player botPlayer;
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
String player;
System.out.println("ENTER bot: ");
player = in.next();
if(player.equalsIgnoreCase("X")) {
botPlayer = Player.X;}
else {botPlayer = Player.O;}
String board[] = new String[3];
for(int i = 0; i < 3; i++) {
System.out.println("ENTER board: ");
board[i] = in.next();
}
currentBoard = new GameBoard(3,3, board);
List<Space> OpenSpaces = getOpenSquares(currentBoard);
MakeMove(OpenSpaces);
System.exit(-1);
}
public static List<Space> getOpenSquares(GameBoard GB) {
List<Space> OpenSpaces = new ArrayList<Space>();
for(int r = 0; r < 3; r++) {
for(int c = 0; c < 3; c++) {
if(GB.squares[r][c] == Player.Open) {
OpenSpaces.add(new Space(r,c));
}
}
}
return OpenSpaces;
}
private static Space bestMove;
private static Space currentMove;
private static Space previousMove;
private static void MakeMove(List<Space> OpenSpaces) {
if(OpenSpaces.size() == currentBoard.Size) {
Random random = new Random();
bestMove = new Space(random.nextInt(2),2);
} else {
for(Space child: OpenSpaces) {
currentMove = GetBestMove(currentBoard,botPlayer);
if (currentMove != null){
}else{
continue;}
if(previousMove != null && previousMove.Rank < currentMove.Rank ||
previousMove == null && currentMove != null) {
bestMove = currentMove;
}
previousMove = currentMove;
}
}
if (bestMove != null) {
currentBoard.squares[bestMove.X][bestMove.Y] = botPlayer;
System.out.println("the best move is: " + currentMove.X + " " + currentMove.Y);
}
}
private static Space GetBestMove(GameBoard gb, Player p) {
Space bestSpace = null;
List<Space> cloneOpenSpaces = getOpenSquares(gb);
GameBoard cloneBoard = null;
cloneBoard = gb.Clone();
for(Space Open: cloneOpenSpaces) {
cloneBoard = gb.Clone();
Space newSpace = Open;
cloneBoard.squares[newSpace.X][newSpace.Y] = p;
if(cloneBoard.Winner == Player.Open && cloneOpenSpaces.size() > 0) {
Player InP;
if(p == Player.X) {
InP = Player.O;
}else {
InP = Player.X;
}
Space tempMove = GetBestMove(cloneBoard, InP);
if(tempMove != null){
newSpace.Rank = tempMove.Rank;
}
} else {
if(cloneBoard.Winner == Player.Open) {
newSpace.Rank = 0;
}else if(cloneBoard.Winner == Player.O) {
newSpace.Rank = -1;
}else if(cloneBoard.Winner == Player.X) {
newSpace.Rank = 1;
}
}
System.out.println(newSpace.Rank);
if(bestSpace == null ||
(p == Player.X && newSpace.Rank < ((Space)bestSpace).Rank)||
(p == Player.O && newSpace.Rank > ((Space)bestSpace).Rank)) {
bestSpace = newSpace;
}
}
return (Space)bestSpace;
}
public static enum Player {
X (1),
O (-1),
Open (0);
private final double value;
Player(double value){
this.value = value;
}
}
public static class Space {
public int X;
public int Y;
public double Rank;
public Space(int x, int y) {
this.X = x;
this.Y = y;
Rank = 0;
}
public Space() {
}
}
public static class GameBoard {
public int Rows;
public int getRows() {
return this.Rows;
}
public void setRows(int rows) {
Rows = rows;
}
public int Columns;
public int getColumns() {
return this.Columns;
}
public void setColumns(int columns) {
Columns = columns;
}
public Player[][] squares;
//public Player[x][y]
public Player getPlayer(int x, int y) {
return this.squares[x][y];
}
public void setPlayer(int x, int y, Player player) {
squares[x][y] = player;
}
public boolean Full;
public boolean isFull() {
for(int r = 0; r < 2; r++) {
for(int c = 0; c < 2; c++) {
if (squares[r][c] != Player.Open) {return false;}
}
}
return true;
}
public int Size;
public int getSize() {
return this.Size;
}
public void setSize(int size) {
Size = size;
}
public List<Space> OpenSquares;
public List<Space> getOpenSquares() {
List<Space> OpenSquares = new ArrayList<Space>();
for(int r = 0; r < Rows; r++) {
for(int c = 0; c < Columns; c++) {
if(squares[r][c] == Player.Open) {
OpenSquares.add(new Space(r,c));
}
}
}
return this.OpenSquares;
}
public Player Winner;
public Player getWinner() {
int count = 0;
//columns
for (int x = 0; x < Rows; x++)
{
count = 0;
for (int y = 0; y < Columns; y++) {
count += squares[x][y].value;
}
if (count == 3) {
return Player.X;
}else if (count == -3) {
return Player.O;
}
}
//rows
for (int x = 0; x < Rows; x++) {
count = 0;
for (int y = 0; y < Columns; y++) {
count += squares[y][x].value;
}
if (count == 3) {
return Player.X;
}else if (count == -3) {
return Player.O;
}
}
// Diagonals right to left
count = 0;
count += squares[0][0].value;
count += squares[1][1].value;
count += squares[2][2].value;
if (count == 3) {
return Player.X;
}else if (count == -3) {
return Player.O;
}
// Diagonals left to right
count = 0;
count += squares[0][2].value;
count += squares[1][1].value;
count += squares[2][0].value;
if (count == 3) {
return Player.X;
}else if (count == -3) {
return Player.O;
}
return Player.Open;
}
public GameBoard Clone() {
GameBoard b = new GameBoard(Rows,Columns);
b.squares = (Player[][])this.squares.clone();
b.Winner = getWinner();
return b;
}
// Class initializer
public GameBoard(int boardRows, int boardColumns, String[] board) {
// Set the dimensions
Rows = boardRows;
Columns = boardColumns;
// Create game spaces
squares = new Player[Rows][Columns];
for(int r = 0; r < Rows; r++) {
for(int c = 0; c < Columns; c++) {
//squares[i][n] = Player.Open;
if(board[r].charAt(c) == 'X') {
squares[r][c] = Player.X;
}
if(board[r].charAt(c) == 'O') {
squares[r][c] = Player.O;
}
if(board[r].charAt(c) == '_') {
squares[r][c] = Player.Open;
}
}
}
this.Winner = getWinner();
this.OpenSquares = getOpenSquares();
//Size of the board
this.Size = Rows * Columns;
}
// clone Class initializer
public GameBoard(int boardRows, int boardColumns) {
// Set the dimensions
Rows = boardRows;
Columns = boardColumns;
// Create game spaces
squares = new Player[Rows][Columns];
for(int r = 0; r < Rows; r++) {
for(int c = 0; c < Columns; c++) {
squares[r][c] = Player.Open;
}
}
this.Winner = getWinner();
this.OpenSquares = getOpenSquares();
//Size of the board
Size = Rows * Columns;
}
}
}
所有课程都在底部。在此先感谢任何帮助和更正。 ：）
我在下面的代码中使它递归，虽然我仍然无法弄清楚得分..如果值是1，0或-1那么如果有多个移动具有相同的值它将只需要1一个可能不是最好的举动“阻止。
private static Space GetBestMove(GameBoard gb, Player p) {
Space bestSpace = null;
List<Space> cloneOpenSpaces = getOpenSquares(gb);
GameBoard cloneBoard = null;
cloneBoard = gb.Clone();
for(Space Open: cloneOpenSpaces) {
cloneBoard = gb.Clone();
Space newSpace = Open;
cloneBoard.squares[newSpace.X][newSpace.Y] = p;
if(cloneBoard.Winner == Player.Open && cloneOpenSpaces.size() > 0) {
Player InP;
if(p == Player.X) {
InP = Player.O;
}else {
InP = Player.X;
}
***Space tempMove = GetBestMove(cloneBoard, InP);***
if(tempMove != null){
newSpace.Rank = tempMove.Rank;
}
测试结果如下
ENTER bot:
O
ENTER board:
[ ][O][ ]
ENTER board:
[ ][ ][ ]
ENTER board:
[ ][X][X]
-1.0
-1.0
-1.0
-1.0
-1.0
-1.0
-1.0
-1.0
-1.0
the best move is: 0 2
ENTER bot:
O
ENTER board:
[ ][X][X]
ENTER board:
[ ][ ][ ]
ENTER board:
[ ][O][ ]
1.0
1.0
1.0
1.0
1.0
-1.0
1.0
-1.0
-1.0
1.0
-1.0
1.0
1.0
-1.0
-1.0
the best move is: 1 1
答案 0 :(得分：2)
我没有运行你的代码，但我想我可能知道你遇到问题的原因。 minimax算法本质上是递归的。您查看每个开放空间，并确定每个空间的某种分数。我在你的代码中看到了这个。然而，我没有看到的是递归等同于逻辑“如果我移动到这里，那么我的对手在下一回合将有什么选择”。请注意，您可以继续调用相同的评分功能，但可以评分两个玩家的选项。这是计算可能变得密集的地方，以及修剪之类的东西。说我想看看前面的3个步骤。假设最初有5个开放空间。对于5个开放空间中的每一个，我检查我的选项并给每个选项分数。然后我假装移动到那里，并通过得分功能发送新板，并假设我的对手将采取其余4个可能移动的最高得分移动。然后我假装他移动到那里，我再次通过评分功能运行板，现在有两个假设的动作。你继续这个设定的“深度”或潜在移动的数量，并选择导致最高值的移动，假设对手将按照你计算的那样做。
我意识到这是啰嗦，但我希望在某处埋藏一点点价值。看看你的代码，找出你得分动作的位置（如果你看到了胜利，就拿它;如果你能阻止胜利，就拿它;等等）。然后继续调用此函数，您可以继续添加假/潜在动作（评分函数中具有最高值的动作），一旦达到深度，您就可以选择可能为您带来最有价值结果的动作。
基本上，在您的代码中，您应该从GetBestMove(...)拨打MakeMove(...)一次。但是，GetBestMove(...)应该反复调用自己，每次修改一次;每次，它都将返回给定假设（或真实）董事会的最佳举措。我在你的代码中没有看到的是对GetBestMove(...)的递归调用，以及随之而来的必要维护。这就解释了为什么你只会采取激进行为;它只是看看最好的直接动作是什么，而不考虑你的对手在你做出这一举动时可能做的事情！
如果我的假设是错误的，请提供一个测试用例，其中您期望某些行为，但会得到不同的结果。