稀疏数组

@Test
public void SparseTest() {
    // 创建一个原始的二维数组 11 * 11
    // 0: 表示没有棋子， 1 表示 黑子 2 表蓝子
    int[][] arr = new int[11][11];
    arr[1][1] = 1;
    arr[2][3] = 2;
    arr[4][5] = 2;
    System.out.println("原始数组");
    for (int[] tmp:arr) {
        for ( int t : tmp) {
            System.out.printf("%d\t",t);
        }
        System.out.println();
    }

    int[][] sparseArr=ArrayToSparse(arr);
    //1.0输出稀疏数组
    System.out.println("输出稀疏数组");
    for (int i = 0; i < sparseArr.length; i++) {
        System.out.printf("%d\t%d\t%d\t",sparseArr[i][0],sparseArr[i][1],sparseArr[i][2]);
        System.out.println();
    }
    //2.0 将系数数组写入文件
    WriteSparseToFile(sparseArr,"xishu.txt");

    //3.0从文件中读出稀疏数组
    System.out.println("从文件中读出稀疏数组");
    int[][] readFileArray = ReadFileToArray("xishu.txt");
    for (int i = 0; i < sparseArr.length; i++) {
        System.out.printf("%d\t%d\t%d\t",sparseArr[i][0],sparseArr[i][1],sparseArr[i][2]);
        System.out.println();
    }
    //4.0从文件中读出稀疏数组,恢复成原来数组
    System.out.println("恢复出来的二维数组");
    int[][] ints = SparseToArray(readFileArray);
    for (int[] tmp:ints) {
        for ( int t : tmp) {
            System.out.printf("%d\t",t);
        }
        System.out.println();
    }
}

 1  //将数组转换为稀疏数组
 2     public int[][] ArrayToSparse(int[][] arr){
 3         //将二维数组转换为稀疏数组
 4         //1.0 遍历得到非零个数
 5         int sum = 0;
 6         for (int i = 0; i < arr.length; i++) {
 7             for (int j = 0; j < arr.length; j++) {
 8                 if(arr[i][j]!=0)
 9                     sum++;
10             }
11         }
12         //2.0创建稀疏数组
13         int[][] sparseArr = new int[sum+1][3];
14         sparseArr[0][0]=11;
15         sparseArr[0][1]=11;
16         sparseArr[0][2] =sum;
17 
18         int count = 0;
19         //3.0遍历 填充稀疏数组非零元素
20         for (int i = 0; i < 11; i++) {
21             for (int j = 0; j <11 ; j++) {
22                 if(arr[i][j]!=0){
23                     ++count;
24                     sparseArr[count][0]=i;
25                     sparseArr[count][1]=j;
26                     sparseArr[count][2]=arr[i][j];
27                 }
28             }
29         }
30 
31         return  sparseArr;
32     }

 1 public void WriteSparseToFile(int[][] sparseArr,String fileName){
 2         FileWriter fw=null;
 3         BufferedWriter bw=null;
 4         try {
 5            fw = new FileWriter(new File(fileName));
 6            bw = new BufferedWriter(fw);
 7             for (int i = 0; i < sparseArr.length; i++) {
 8 
 9                 String tmpStr ="";
10                 for (int j = 0; j <sparseArr[i].length ; j++) {
11                     tmpStr+=sparseArr[i][j]+" ";
12                 }
13                 tmpStr+="\r\n";
14                 bw.write(tmpStr);
15                 bw.flush();
16             }
17         } catch (IOException e) {
18             e.printStackTrace();
19         }finally {
20             if(bw!=null) {
21                 try {
22                     bw.close();
23                 } catch (IOException e) {
24                     e.printStackTrace();
25                 }
26             }
27             if(fw!=null){
28                 try {
29                     fw.close();
30                 } catch (IOException e) {
31                     e.printStackTrace();
32                 }
33             }
34 
35         }
36     }

 1 public int[][] ReadFileToArray(String fileName){
 2         FileReader fr = null;
 3         BufferedReader br = null;
 4         int[][] readArray={};
 5         try {
 6             fr = new FileReader(new File(fileName));
 7             br = new BufferedReader(fr);
 8 
 9             String lineStr="";
10             ArrayList<String> list = new ArrayList<>();
11             try {
12                 while ((lineStr= br.readLine())!=null){
13                     list.add(lineStr);
14                 }
15                 readArray = new int[list.size()][list.get(0).length()];
16                 for (int i = 0;i<list.size() ; i++) {
17                     String[] c = list.get(i).split(" ");
18                     for (int j = 0; j <c.length ; j++) {
19                         readArray[i][j]=Integer.parseInt(c[j]);
20                     }
21                 }
22             } catch (IOException e) {
23                 e.printStackTrace();
24             }
25         } catch (FileNotFoundException e) {
26             e.printStackTrace();
27         }finally {
28             if(br!=null) {
29                 try {
30                     br.close();
31                 } catch (IOException e) {
32                     e.printStackTrace();
33                 }
34             }
35             if(fr!=null){
36                 try {
37                     fr.close();
38                 } catch (IOException e) {
39                     e.printStackTrace();
40                 }
41             }
42             return  readArray;
43         }
44 
45 
46     }

 1  //将稀疏数组转换为数组
 2     public int[][] SparseToArray(int[][] sparseArr){
 3         //将稀疏数组恢复成数组
 4         //1.0先读取稀疏数组的第一行，根据第一行的数据，创建原始的二维数组
 5         int[][] arr  = new int[sparseArr[0][0]][sparseArr[0][1]];
 6         //2.0在读取稀疏数组后几行的数据(从第二行开始)，并赋给 原始的二维数组 即可
 7         for (int i = 1; i <sparseArr.length ; i++) {
 8             arr[sparseArr[i][0]][sparseArr[i][1]]=sparseArr[i][2];
 9         }
10 
11         return arr;
12     }