稀疏数组

类似棋盘上的棋子：

用二维数组保存：

用稀疏数组来保存：

public class XiShu {
    public static void main(String[] args) {
        //创造二维数组
        int[][] array1 = new int[7][6];
        array1[0][0] = 2;
        array1[5][4] = 4;
        System.out.println("该数组为：");
        //增强for循环遍历数组元素
        for (int[] ints : array1) {
            for (int anInt : ints) {
                System.out.print(anInt + "\t");
            }
            System.out.println();
        }
        //转换为稀疏数组
        //有效值个数
        int sum = 0;
        for (int i = 0; i < array1.length; i++) {
            for (int j = 0; j < array1[i].length; j++) {
                if (array1[i][j] != 0) {
                    sum++;
                }
            }
        }
        System.out.println("有效值个数为:" + sum);
        int[][] array2 = new int[sum + 1][3];
        array2[0][0] = 7;
        array2[0][1] = 6;
        array2[0][2] = sum;
        //创建稀疏数组
        int count = 0;
        for (int i = 0; i < array1.length; i++) {
            for (int j = 0; j < array1[i].length; j++) {
                if (array1[i][j] != 0) {
                    count++;
                    array2[count][0] = i;
                    array2[count][1] = j;
                    array2[count][2] = array1[i][j];

                }
            }
        }
        //输出数组
        System.out.println("===========================================");
        for (int i = 0; i < array2.length; i++) {
            System.out.println(array2[i][0] + "\t" + array2[i][1] + "\t" + array2[i][2]);

        }

//还原
        System.out.println("还原的数组为：===========================================");
        int[][] array3 = new int[array2[0][0]][array2[0][1]];
        for (int i = 1; i < array2.length; i++) {
            array3[array2[i][0]][array2[i][1]] = array2[i][2];
        }
        for (int[] ints : array3) {
            for (int anInt : ints) {
                System.out.print(anInt + "\t");
            }
            System.out.println();
        }
    }


}

哈哈哈！！！