用java 写一个 2048 小游戏

好的，以下是 Java 实现的 2048 小游戏代码：

import java.util.*;

public class Game2048 {
    private final int size = 4;
    private int[][] grid;
    private Random rand;

    public Game2048() {
        grid = new int[size][size];
        rand = new Random();
        addRandomTile();
        addRandomTile();
    }

    private void addRandomTile() {
        List<int[]> emptyCells = new ArrayList<>();
        for (int i = 0; i < size; i++) {
            for (int j = 0; j < size; j++) {
                if (grid[i][j] == 0) {
                    emptyCells.add(new int[]{i, j});
                }
            }
        }
        if (!emptyCells.isEmpty()) {
            int[] chosenCell = emptyCells.get(rand.nextInt(emptyCells.size()));
            grid[chosenCell[0]][chosenCell[1]] = (rand.nextDouble() < 0.9) ? 2 : 4;
        }
    }

    public void move(Direction direction) {
        boolean hasMoved = false;
        switch (direction) {
            case UP:
                for (int j = 0; j < size; j++) {
                    int[] col = getColumn(j);
                    int[] newCol = merge(col);
                    setColumn(j, newCol);
                    if (!hasMoved && !Arrays.equals(col, newCol)) {
                        hasMoved = true;
                    }
                }
                break;
            case DOWN:
                for (int j = 0; j < size; j++) {
                    int[] col = getColumn(j);
                    int[] newCol = merge(reverse(col));
                    setColumn(j, reverse(newCol));
                    if (!hasMoved && !Arrays.equals(col, newCol)) {
                        hasMoved = true;
                    }
                }
                break;
            case LEFT:
                for (int i = 0; i < size; i++) {
                    int[] row = getRow(i);
                    int[] newRow = merge(row);
                    setRow(i, newRow);
                    if (!hasMoved && !Arrays.equals(row, newRow)) {
                        hasMoved = true;
                    }
                }
                break;
            case RIGHT:
                for (int i = 0; i < size; i++) {
                    int[] row = getRow(i);
                    int[] newRow = merge(reverse(row));
                    setRow(i, reverse(newRow));
                    if (!hasMoved && !Arrays.equals(row, newRow)) {
                        hasMoved = true;
                    }
                }
                break;
        }
        if (hasMoved) {
            addRandomTile();
        }
    }

    private int[] getColumn(int j) {
        int[] col = new int[size];
        for (int i = 0; i < size; i++) {
            col[i] = grid[i][j];
        }
        return col;
    }

    private void setColumn(int j, int[] col) {
        for (int i = 0; i < size; i++) {
            grid[i][j] = col[i];
        }
    }

    private int[] getRow(int i) {
        return grid[i];
    }

    private void setRow(int i, int[] row) {
        grid[i] = row;
    }

    private int[] merge(int[] cells) {
        int[] newCells = new int[size];
        int writePos = 0;
        for (int i = 0; i < size; i++) {
            if (cells[i] != 0) {
                if (writePos > 0 && newCells[writePos - 1] == cells[i]) {
                    newCells[writePos - 1] *= 2;
                } else {
                    newCells[writePos++] = cells[i];
                }
            }
        }
        return newCells;
    }

    private int[] reverse(int[] cells) {
        int[] newCells = new int[size];
        for (int i = 0; i < size; i++) {
            newCells[i] = cells[size - i - 1];
        }
        return newCells;
    }

    public boolean isGameOver() {
        if (getEmptyCells().size() > 0) {
            return false;
        }
        for (int i = 0; i < size; i++) {
            for (int j = 0; j < size; j++) {
                int cellValue = grid[i][j];
                if (i > 0 && grid[i - 1][j] == cellValue) {
                    return false;
                }
                if (i < size - 1 && grid[i + 1][j] == cellValue) {
                    return false;
                }
                if (j > 0 && grid[i][j - 1] == cellValue) {
                    return false;
                }
                if (j < size - 1 && grid[i][j + 1] == cellValue) {
                    return false;
                }
            }
        }
        return true;
    }

    private List<int[]> getEmptyCells() {
        List<int[]> emptyCells = new ArrayList<>();
        for (int i = 0; i < size; i++) {
            for (int j = 0; j < size; j++) {
                if (grid[i][j] == 0) {
                    emptyCells.add(new int[]{i, j});
                }
            }
        }
        return emptyCells;
    }

    public void print() {
        for (int i = 0; i < size; i++) {
            for (int j = 0; j < size; j++) {
                System.out.print(grid[i][j] + "\t");
            }
            System.out.println();
        }
    }

    public static void main(String[] args) {
        Game2048 game = new Game2048();
        Scanner scanner = new Scanner(System.in);
        while (!game.isGameOver()) {
            game.print();
            System.out.print("Enter direction (up/down/left/right): ");
            String input = scanner.nextLine();
            switch (input) {
                case "up":
                    game.move(Direction.UP);
                    break;
                case "down":
                    game.move(Direction.DOWN);
                    break;
                case "left":
                    game.move(Direction.LEFT);
                    break;
                case "right":
                    game.move(Direction.RIGHT);
                    break;
                default:
                    System.out.println("Invalid input");
                    break;
            }
        }
        System.out.println("Game over!");
        game.print();
    }

    private enum Direction {
        UP, DOWN, LEFT, RIGHT
    }
}

以上代码实现了 2048 小游戏的核心逻辑，包括添加随机方块、合并方块、移动方块、判断是否结束等功能，并提供了一个简单的命令行界面供玩家操作。