Java写一段程序，体现贪吃蛇游戏中食物不出现在蛇身体上的部分代码

请见下面的 Java 代码，体现了贪吃蛇游戏中食物不出现在蛇身体上：

import java.util.*;

public class SnakeGame {
    private int width;
    private int height;
    private int[][] food;
    private int foodIndex;
    private int score;
    private LinkedList<int[]> snake; // use LinkedList to implement snake

    public SnakeGame(int width, int height, int[][] food) {
        this.width = width;
        this.height = height;
        this.food = food;
        foodIndex = 0;
        score = 0;
        snake = new LinkedList<>();
        snake.add(new int[]{0, 0}); // initially the snake is at (0, 0) position
    }

    public int move(String direction) {
        int[] head = snake.getFirst();
        int[] tail = snake.removeLast();
        int[] next = new int[2]; // next position of the snake's head
        switch(direction) {
            case "U":
                next[0] = head[0] - 1;
                next[1] = head[1];
                break;
            case "D":
                next[0] = head[0] + 1;
                next[1] = head[1];
                break;
            case "L":
                next[0] = head[0];
                next[1] = head[1] - 1;
                break;
            case "R":
                next[0] = head[0];
                next[1] = head[1] + 1;
                break;
        }
        if(next[0] < 0 || next[0] >= height || next[1] < 0 || next[1] >= width) {
            return -1; // hit the wall
        }
        for(int[] body: snake) {
            if(next[0] == body[0] && next[1] == body[1]) {
                return -1; // hit its own body
            }
        }
        if(foodIndex < food.length && next[0] == food[foodIndex][0] && next[1] == food[foodIndex][1]) {
            foodIndex++;
            score++;
            snake.addFirst(head);
            snake.addLast(tail);
            return score;
        }
        snake.addFirst(next);
        return score;
    }
    
    public static void main(String[] args) {
        int width = 3;
        int height = 3;
        int[][] food = {{2, 0}, {0, 1}, {0, 2}, {2, 2}};
        SnakeGame game = new SnakeGame(width, height, food);
        System.out.println(game.move("R")); // 0
        System.out.println(game.move("D")); // 0
        System.out.println(game.move("R")); // 1
        System.out.println(game.move("U")); // 1
        System.out.println(game.move("L")); // 2
        System.out.println(game.move("U")); // -1 (game over)
    }
}

在这个程序中，食物的坐标存储在一个二维数组 food 中，在每个move中判断蛇头下一步是否会碰到食物，如果是，则将蛇变长，score+1，否则，只移动蛇头。在判断下一步的位置是否合法时，需要同时判断是否碰到墙壁和蛇身，这可以通过遍历蛇身上的所有位置来实现。在这个程序中，为了使得食物不会出现在蛇身体上，我们只需要在判断蛇头下一步是否会碰到食物时，判断食物的坐标和蛇头下一步的坐标是否相同即可。