我已经为实现MiniMax算法的tic-tac-toe AI编写了这段代码。 AI每次都获胜（全深度搜索）。但可能有些不对劲。这是让我怀疑实现正确性的输出：
0 0 0
0 0 0
0 0 0
Who's gonna move first? (1) You : (2) Me?
1
Your move:
2 2
0 0 0
0 0 0
0 0 2
Score: -1 Point: 0 0
Score: -1 Point: 0 1
Score: -1 Point: 0 2
Score: -1 Point: 1 0
Score: 0 Point: 1 1
Score: 0 Point: 1 2
Score: 0 Point: 2 0
Score: 0 Point: 2 1
0 0 0
0 1 0
0 0 2
Your move:
0 0
2 0 0
0 1 0
0 0 2
Score: 0 Point: 0 1
Score: 0 Point: 0 2
Score: 0 Point: 1 0
Score: 0 Point: 1 2
Score: 0 Point: 2 0
Score: 0 Point: 2 1
2 1 0
0 1 0
0 0 2
现在这些点的所有0都意味着AI可以在最坏的情况下绘制匹配，如果轮到并将这些点标记为1.（AI为1，Player为2）。这绝对是错误的。有两点可以肯定失败（点0 2和点2 0）所以在这些点上得分必须为-1。但AI采取了第一步并获胜（为什么？）。即使有成千上万的随机测试，我也无法击败AI。
这是完整的代码。如果你能告诉我出错的事情，那将是非常有帮助的。
import java.util.*;
class Point {
int x, y;
public Point(int x, int y) {
this.x = x;
this.y = y;
}
}
public class Board {
//Copy constructor
public Board(Board b) {
for (int i = 0; i < 3; ++i) {
for (int j = 0; j < 3; ++j) {
this.board[i][j] = b.board[i][j];
}
}
}
public Board() {
}
int[][] board = new int[3][3];
List<Point> availablePoints;
//Get the playable locations available on the board
public List<Point> getAvailableStates() {
availablePoints = new ArrayList<>();
for (int i = 0; i < 3; ++i) {
for (int j = 0; j < 3; ++j) {
if (board[i][j] == 0) {
availablePoints.add(new Point(i, j));
}
}
}
return availablePoints;
}
public boolean isGameOver() {
//Game is over is someone has won, or board is full (draw)
return (hasXWon() || hasOWon() || getAvailableStates().isEmpty());
}
public boolean hasXWon() {
if ((board[0][0] == board[1][1] && board[0][0] == board[2][2] && board[0][0] == 1)
|| (board[0][2] == board[1][1] && board[0][2] == board[2][0] && board[0][2] == 1)) {
//System.out.println("X Diagonal Win");
return true;
}
for (int i = 0; i < 3; ++i) {
if (((board[i][0] == board[i][1] && board[i][0] == board[i][2] && board[i][0] == 1)
|| (board[0][i] == board[1][i] && board[0][i] == board[2][i] && board[0][i] == 1))) {
//System.out.println("X Row or Column win");
return true;
}
}
return false;
}
public boolean hasOWon() {
if ((board[0][0] == board[1][1] && board[0][0] == board[2][2] && board[0][0] == 2)
|| (board[0][2] == board[1][1] && board[0][2] == board[2][0] && board[0][2] == 2)) {
//System.out.println("O Diagonal Win");
return true;
}
for (int i = 0; i < 3; ++i) {
if ((board[i][0] == board[i][1] && board[i][0] == board[i][2] && board[i][0] == 2)
|| (board[0][i] == board[1][i] && board[0][i] == board[2][i] && board[0][i] == 2)) {
//System.out.println("O Row or Column win");
return true;
}
}
return false;
}
public void placeAMove(Point point, int player) {
board[point.x][point.y] = player; //player = 1 for X, 2 for O
}
class PointsAndScores {
int score;
Point point;
PointsAndScores(int score, Point point) {
this.score = score;
this.point = point;
}
}
List<PointsAndScores> pointsAndScores = new ArrayList<>();
//The actual MinMax Logic is in this function
public int evaluateBoardPositions(int RecursionTurn) {
List<Point> availablePoints = getAvailableStates();
if (hasXWon()) {
return +1;
} else if (hasOWon()) {
return -1;
} else if (availablePoints.isEmpty()) {
return 0;
} else {
int minOrMax = -999;
List<Integer> scores = new ArrayList<>();
for (Point point : availablePoints) {
Board newBoard = new Board(this);
if (RecursionTurn == 1) {
newBoard.placeAMove(point, 1);
scores.add(newBoard.evaluateBoardPositions(2));
Collections.sort(scores, Collections.reverseOrder());
minOrMax = scores.get(0);
}
if (RecursionTurn == 2) {
newBoard.placeAMove(point, 2);
scores.add(newBoard.evaluateBoardPositions(1));
Collections.sort(scores);
minOrMax = scores.get(0);
}
pointsAndScores.add(new PointsAndScores(minOrMax, point));
}
return minOrMax;
}
}
//Return the move with the highest score i.e. +1 for our Bot.
public Point returnBestMove() {
int MAX = -100000;
int best = -1;
for (int i = 0; i < pointsAndScores.size(); ++i) {
if (MAX < pointsAndScores.get(i).score) {
MAX = pointsAndScores.get(i).score;
best = i;
}
}
return pointsAndScores.get(best).point;
}
Scanner scan = new Scanner(System.in);
void takeHumanInput() {
System.out.println("Your move: ");
int x = scan.nextInt();
int y = scan.nextInt();
Point point = new Point(x, y);
placeAMove(point, 2);
}
public void displayBoard() {
System.out.println();
for (int i = 0; i < 3; ++i) {
for (int j = 0; j < 3; ++j) {
System.out.print(board[i][j] + " ");
}
System.out.println();
}
}
void placeFirstMove() {
Random rand = new Random();
Point p = new Point(rand.nextInt(3), rand.nextInt(3));
placeAMove(p, 1);
}
public static void main(String[] args) {
Board b = new Board();
b.displayBoard();
System.out.println("Who's gonna move first? (1) You : (2) Me?");
Scanner scan = new Scanner(System.in);
int choice = scan.nextInt();
if (choice == 2) {
b.placeFirstMove();
b.displayBoard();
}
while (!b.isGameOver()) {
b.takeHumanInput();
if (b.isGameOver()) {
break;
}
b.displayBoard();
b.pointsAndScores.clear();
b.evaluateBoardPositions(1);
Point p = b.returnBestMove();
for (PointsAndScores pas : b.pointsAndScores) {
System.out.println("Score: " + pas.score + " Point: " + pas.point.x + " " + pas.point.y);
}
b.placeAMove(p, 1);
b.displayBoard();
}
if (b.hasXWon()) {
System.out.println("Unfortunately, you lost!");
} else if (b.hasOWon()) {
System.out.println("Never gets displayed. Computer Always wins or draws");
} else {
System.out.println("It's a draw!");
}
}
}
答案 0 :(得分：0)
public int evaluateBoardPositions(int RecursionTurn, int bestPoint) {
List<Point> availablePoints = getAvailableStates();
int minOrMax = -999;
if (hasXWon()) {
return +1;
} else if (hasOWon()) {
return -1;
} else if (availablePoints.isEmpty()) {
return 0;
}
else {
for (Point point : availablePoints) {
Board newBoard = new Board(this);
if (RecursionTurn == 1) {
newBoard.placeAMove(point, 1);
bestPoint = newBoard.evaluateBoardPositions(2,bestPoint);
pointsAndScores.add(new PointsAndScores(bestPoint, point));
Collections.sort(pointsAndScores);
minOrMax = pointsAndScores.get(pointsAndScores.size()-1).score;
}
else {
newBoard.placeAMove(point, 2);
bestPoint = newBoard.evaluateBoardPositions(1,bestPoint);
pointsAndScores.add(new PointsAndScores(bestPoint, point));
Collections.sort(pointsAndScores);
minOrMax = pointsAndScores.get(0).score;
}
}
return minOrMax;
}
}