Java的：的ArrayList的二维数组？ [英] Java: 2D array of arraylists?

问题描述

我工作的一个数独的解决方案，我需要保存数字1到9每个在9x9的板正方形的ArrayList。所有这些的ArrayLists的对应可能的数字，可以去在广场上，如果一个数字不能在广场去，这是从列表中删除。

I am working on a sudoku solving program and I need an arraylist that holds the numbers 1 thru 9 for each of the squares on the 9x9 board. Each of these arraylists correspond to the possible numbers that could go in that square, if a number can not go in that square, it is removed from the list.

我希望能够拉起它正在研究，例如像当前方块的数组列表，如果我想从对应方ArrayList中取出7号（3,5）

I want to be able to pull up the arraylist of the current square it is working on, like for example if I wanted to remove the number 7 from the arraylist corresponding to square (3,5)

arrayOfLists[3][5].remove(Integer.valueOf(7));

不过，我无法弄清楚如何做到这一点。当我尝试创建我就行了获取此错误的数组，其中我宣布我的ArrayList数组

However I can't figure out how to do this. When I try to create the array I am getting this error on the line where I declare my array of arraylists

无法创建ArrayList的一个通用阵列

Cannot create a generic array of ArrayList

下面是我的code：

    //create arraylist
    ArrayList<Integer> nums = new ArrayList<Integer>();

    //fill arraylist with numbers 1-9
    for (int i = 1; i < 10; i++) {
        nums.add(i);
    }

    //create 9x9 array of arraylists
    ArrayList<Integer>[][] array = new ArrayList<Integer>[9][9];

    //fill each element of array with arraylist of numbers 1-9
    for(int i = 0; i<9; i++){
        for(int j = 0; j<9; j++){
            array[i][j] = nums;
        }       
    }

}

我是否正确做这个或者是无法创建的ArrayList数组？如果这是不可能的，我应该怎么做呢？

Am I doing this incorrectly or is it not possible to create an array of arraylists? If it is not possible, how should I do this then?

推荐答案

使用位字段，而不是一个数组列表中。也就是说，使用所有位1-9重新present号码的可能性整数。测试，添加，删除一个数字是O（1），它有一个固定的存储器大小。封装在自己的对象，知道行动的整数。

Use a bit field instead of an array list. That is, use an integer where bits 1-9 represent the possibilities of the numbers. Testing, adding, removing a single number is O(1), and it has a fixed memory size. Encapsulate the integer in its own object that knows the operations.

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