数据结构与算法之稀疏数组

 1 public class SparseArray {
 2     public static void main(String[] args) throws IOException, ClassNotFoundException {
 3         //创建一个二维数组
 4         int arr1[][] = new int[11][11];
 5         arr1[1][2] = 1;
 6         arr1[2][3] = 2;
 7         arr1[2][4] = 1;
 8         
 9         //输出打印
10         System.out.println("新的二维数组：");
11         for (int[] rows : arr1) {
12             for (int i : rows) {
13                 System.out.print(i+"\t");
14             }
15             System.out.println();
16         }
17         System.out.println();
18 
19         //获取二维数组的行数、列数
20         int rowNum = arr1.length;
21         int colNum = arr1[0].length;
22         //获取非零数个数
23         int valNum = 0;
24         for (int[] rows : arr1) {
25             for (int i : rows) {
26                 if (i != 0){
27                     valNum++;
28                 }
29             }
30         }
31         
32         //依照获取的数据创建一个稀疏数组
33         int sparseArr[][] = new int[valNum+1][3];
34         
35         //设置第一行数据
36         sparseArr[0][0] = rowNum;
37         sparseArr[0][1] = colNum;
38         sparseArr[0][2] = valNum;
39         
40         //计数器
41         int count = 0;
42         for (int i = 0; i < arr1.length; i++) {
43             for (int j = 0; j < arr1[i].length; j++) {
44                 if (arr1[i][j] != 0){
45                     count++;
46                     //第n个非零数在稀疏数组中的行下标为n+1
47                     sparseArr[count][0] = i;
48                     sparseArr[count][1] = j;
49                     sparseArr[count][2] = arr1[i][j];
50                 }
51             }
52         }
53         
54         //打印稀疏数组
55         for (int[] rows : sparseArr) {
56             for (int i : rows) {
57                 System.out.print(i+"\t");
58             }
59             System.out.println();
60         }
61         System.out.println();
62 
63         //用对象输出流写入文件中
64         ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("G:\\Files\\test\\sparseArr.txt"));
65         oos.writeObject(sparseArr);
66         
67         //用对象输入流读入文件中的对象
68         ObjectInputStream ois = new ObjectInputStream(new FileInputStream("G:\\Files\\test\\sparseArr.txt"));
69         int[][] sparseArr2 = (int[][]) ois.readObject();
70         
71         //打印验证数据还原
72         System.out.println("还原的稀疏数组：");
73         for (int[] rows : sparseArr2) {
74             for (int i : rows) {
75                 System.out.print(i+"\t");
76             }
77             System.out.println();
78         }
79         System.out.println();
80 
81 
82         //将稀疏数组还原为原来的二维数组
83         int arr2[][] = new int[sparseArr2[0][0]][sparseArr2[0][1]];
84         for (int i = 1; i < sparseArr2.length; i++) {
85             arr2[sparseArr2[i][0]][sparseArr2[i][1]] = sparseArr2[i][2];
86         }
87         
88         //再次打印验证
89         for (int[] rows : arr2) {
90             for (int i : rows) {
91                 System.out.print(i+"\t");
92             }
93             System.out.println();
94         }
95 
96     }
97 }