稀疏数组基本介绍
当一个数组中大部分元素为０，或者为同一个值的数组时，可以使用稀疏数组来保存该数组
- 记录数组一共有几行几列，有多少个不同的值
- 把具有不同值的元素的行列及值记录在一个小规模的数组中，从而缩小程序的规模
图解：
代码实现
package com.atschool.sparsearr;
import java.io.*;
/**
* Description:
* Author:江洋大盗
* Date:2020/11/28 22:01
*/
public class SparseArr {
public static void main(String[] args) {
SparseArr sparseArr = new SparseArr();
int[][] arr01 = new int[11][11];
arr01[1][2] = 1;
arr01[2][3] = 2;
sparseArr.showArr(arr01);
int sum = 0;
for (int[] ints : arr01) {
for (int anInt : ints) {
if (anInt != 0) {
sum++;
}
}
}
int[][] arr02 = new int[sum + 1][3];
arr02[0][0] = 11;
arr02[0][1] = 11;
arr02[0][2] = sum;
int count = 0;
for (int i = 0; i < arr01.length; i++) {
for (int j = 0; j < arr01[i].length; j++) {
if (arr01[i][j] != 0) {
count++;
arr02[count][0] = i;
arr02[count][1] = j;
arr02[count][2] = arr01[i][j];
}
}
}
sparseArr.showArr(arr02);
sparseArr.write(arr02);
int[][] arr03 = (int[][]) sparseArr.read(new File("E:\\ioTest\\sparseArr.dat"));
System.out.println("-------------------------");
assert arr03 != null;
sparseArr.showArr(arr03);
int[][] arr04 = new int[arr03[0][0]][arr03[0][1]];
for (int i = 1; i < arr03.length; i++) {
arr04[arr03[i][0]][arr03[i][1]] = arr03[i][2];
}
System.out.println("----------------------");
sparseArr.showArr(arr04);
}
private void showArr(int[][] arr) {
for (int[] ints : arr) {
for (int anInt : ints) {
System.out.print(anInt + "\t");
}
System.out.println();
}
}
private void write(Object obj) {
ObjectOutputStream oos = null;
try {
FileOutputStream fos = new FileOutputStream(new File("E:\\ioTest\\sparseArr.dat"));
oos = new ObjectOutputStream(fos);
oos.writeObject(obj);
oos.flush();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (oos != null) {
try {
oos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
private Object read(File file) {
ObjectInputStream ois = null;
try {
FileInputStream fis = new FileInputStream(file);
ois = new ObjectInputStream(fis);
return ois.readObject();
} catch (IOException | ClassNotFoundException e) {
e.printStackTrace();
} finally {
if (ois != null) {
try {
ois.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return null;
}
}
结语
只要能收获甜蜜，荆棘丛中也有蜜蜂忙碌的身影，未来的你一定会感谢现在努力的自己。