public class demo04 {
    public static void main(String[] args) {
        int[][] arr1 = new int[11][11];
        arr1[1][2] = 1;
        arr1[2][3] = 1;
        for (int[] ints : arr1) {
            for (int anInt : ints) {
                System.out.print(anInt+"\t");
            }
            System.out.println();
        }
        System.out.println("======================");

        //转化为稀疏数组保存
        //获取有效的个数

        int sum = 0;
        for (int i = 0; i < 11; i++){
            for (int j = 0; j < 11; j++){
                if (arr1[i][j]!=0)
                    sum++;
            }
        }
        int arr2[][] = new int[sum+1][3];
        arr2[0][0] = 11;
        arr2[0][1] = 11;
        arr2[0][2] = sum;

        //遍历二维数组，将非零的数值保存并存放稀疏数组
        int count = 0;
        for (int i = 0; i < arr1.length; i++){
            for (int j = 0; j < arr1[i].length; j++){
                if (arr1[i][j]!=0) {
                    count++;
                    arr2[count][0] = i;
                    arr2[count][1] = j;
                    arr2[count][2] = arr1[i][j];
                }
            }
        }
        for (int[] ints : arr2) {
            for (int anInt : ints) {
                System.out.print(anInt+"\t");
            }
            System.out.println();
        }
        System.out.println("======================");

        //将稀疏数组转化为普通数组
        int[][] arr3 = new int[arr2[0][0]][arr2[0][1]];
        for (int i = 1; i < arr2.length; i++){
            arr3[arr2[i][0]][arr2[i][1]] = arr2[i][2];
        }
        for (int[] ints : arr3) {
            for (int anInt : ints) {
                System.out.print(anInt+"\t");
            }
            System.out.println();
        }


    }
}

输出结果：