稀疏数组

public class ArraysDemo02 {
public static void main(String[] args) {
int[][] a = new int[11][11];
a[1][2] = 1;
a[2][3] = 2;
for (int[] ints : a) {
for (int i : ints) {
System.out.print(i + " \t");
}
System.out.println();
}
System.out.println("============");
//转换为稀疏数组保存
//获取有效值的个数
int sum = 0;
for (int i = 0; i < a.length; i++) {
for (int j = 0; j < a.length; j++) {
if (a[i][j] != 0) {
sum++;
}
}
}
System.out.println("有效值的个数：" + sum);
//创建一个稀疏数组的数组
int[][] a2 = new int[sum + 1][3];
a2[0][0] = 11;
a2[0][1] = 11;
a2[0][2] = sum;

    //遍历二维数组，将非零的值存放在稀疏数组中
    int count = 0;
    for (int i = 0; i < a.length; i++) {
        for (int j = 0; j < a[i].length; j++) {
            if (a[i][j] != 0) {
                count++;
                a2[count][0] = i;
                a2[count][1] = j;
                a2[count][2] = a[i][j];
            }

        }


    }
    //输出稀疏数组
    System.out.println("稀疏数组");
    for (int i = 0; i < a2.length; i++) {
        System.out.println(a2[i][0] + "\t" + a2[i][1] + "\t" + a2[i][2]);
        System.out.println();
    }
    System.out.println("==============");
    System.out.println("还原");
    //读取稀疏数组
    int[][] a3 = new int[a2[0][0]][a2[0][1]];
    //给其中的元素还原值
    for (int i = 1; i < a2.length; i++) {
        a3[a2[i][0]][a2[i][1]] = a2[i][2];
    }
    //打印

    System.out.println("还原的数组");

    for (int[] ints : a) {
        for (int i : ints) {
            System.out.print(i + " \t");
        }
        System.out.println();


    }

}

}