Linear and nonlinear structures

Linear structure and nonlinear structure

Because many of the default values for two-dimensional arrays are 0, So a lot of meaningless data was recorded –> Sparse array

Illustrate with examples ：

Application example ：

Array conversion analysis ：

public class demo {
    
    public static void main(String[] args) {
    
        // Create an original 11*11 Two dimensional array of 
        //0 No chess pieces  1 White chess  2 Indicates blue chess 
        int chessArr1[][] = new int[11][11];
        chessArr1[1][2] = 1;
        chessArr1[2][3] = 2;
        // Output the original two-dimensional array 
        System.out.println(" The original two-dimensional array :");
        for (int[] row : chessArr1) {
    
            for (int data : row) {
    
                System.out.printf("%d\t", data);
            }
            System.out.println();
        }
        // The idea of converting a two-dimensional array into a sparse array 
        //1. First, traverse the two-dimensional array   Get the blame 0 The number of data 
        int sum = 0;
        for (int i = 0; i < 11; i++) {
    
            for (int j = 0; j < 11; j++) {
    
                if (chessArr1[i][j] != 0) {
    
                    sum++;
                }
            }
        }
        //2. Create the corresponding sparse array 
        int sparseArr[][] = new int[sum + 1][3];
        // Assign values to sparse arrays 
        sparseArr[0][0] = 11;
        sparseArr[0][1] = 11;
        sparseArr[0][2] = sum;
        //3. Traversing a two-dimensional array   Will not 0 Data stored in sparseArr in 
        int count = 1;// Used to record the number of non 0 data 
        for (int i = 0; i < 11; i++) {
    
            for (int j = 0; j < 11; j++) {
    
                if (chessArr1[i][j] != 0) {
    
                    sparseArr[count][0] = i;
                    sparseArr[count][1] = j;
                    sparseArr[count][2] = count;
                    count++;
                }
            }
        }
        // Output sparse array form 
        System.out.println();
        System.out.println(" The resulting sparse array is :");
        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();
        }
        // Restore the sparse array to the original two-dimensional array 
        //1. First read the first row of the sparse array , According to the data in the first line , Create the original two-dimensional array 
        int[][] chessArr2=new int[sparseArr[0][0]][sparseArr[0][1]];
        //2. A few lines after reading the sparse array ( Start with the second line ) data , And assign it to the original two-dimensional array 
        for (int i=1;i<sparseArr.length;i++){
    
            chessArr2[sparseArr[i][0]][sparseArr[i][1]]=sparseArr[i][2];
        }
        // Output the recovered 2D array 
        System.out.println();
        for (int[] row : chessArr2) {
    
            for (int data : row) {
    
                System.out.printf("%d\t", data);
            }
            System.out.println();
        }
    }
}