java - 如何使用各自的数组 ID 或值对数组进行排序？

Question

我有两个数组:

 String [] ids= new String [5];
 String [] points= new String [5];

 String one="a,b,c,d,e";
 //or
 String one="nepal,japan,finland ,brazil,spain";
 String two="100,500,200,400,300";
 ids= one.split(",");
 points= two.split(",");

现在我想按降序对 points 进行排序。

500,400,300,200,100 with respective ids b,d,e,c,a

我该怎么做。

但我尝试按降序排列，这没问题，但是如何使用各自的 id 对 id 进行排序。

 Arrays.sort(points, Collections.reverseOrder());
 Arrays.toString(points);

或

Arrays.sort(points);

如果我做同样的 ids 也是降序的。但这不是输出。

已编辑:

如果我有替换

a,b,c,d,e 给国家名称或时间的字母。

String one="a,b,c,d,e";
//  or
String countries = "nepal,japan,finland,brazil,spain";
// or
String time="0:10,1:25,4:00,2:10,0:55";

Answer 1

你可以定义你自己的Comparator，像这样:

import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;

public class CustomArrayComparator implements Comparator<String>
{
    private String[] pointsArray;
    private Map<String, Integer> idsMap;

    public CustomArrayComparator(String[] pointsArray, String[] countriesArray)
    {
        this.pointsArray = pointsArray;
        idsMap = new HashMap<String, Integer>();
        for(int i = 0; i < pointsArray.length; i++) idsMap.put(countriesArray[i], i);
    }

    @Override
    public int compare(String s1, String s2)
    {   
        return pointsArray[idsMap.get(s2)].compareTo(pointsArray[idsMap.get(s1)]);
    }
}

这里是主要的:

String[] points = {"100", "500", "200", "400", "300"};
String[] countries = {"nepal", "japan", "finland", "brazil", "spain"};
CustomArrayComparator comparator = new CustomArrayComparator(points, countries);
Arrays.sort(countries, comparator);
Arrays.sort(points, Collections.reverseOrder());

System.out.println(Arrays.toString(points));
System.out.println(Arrays.toString(countries));

输出:

[500, 400, 300, 200, 100]
[japan, brazil, spain, finland, nepal]

---

编辑:

作为通用类，这里是具有通用实现的同一个类:

import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;

public class CustomArrayComparator<T extends Comparable<T>, E> implements Comparator<T>
{
    private T[] mainArray;
    private Map<E, Integer> indexesMap;

    public CustomArrayComparator(T[] mainArray, E[] associatedArray)
    {
        this.mainArray = mainArray;
        indexesMap = new HashMap<E, Integer>();
        for(int i = 0; i < mainArray.length; i++)
        {
            indexesMap.put(associatedArray[i], i);
        }
    }

    @Override
    public int compare(T t1, T t2)
    {   
        return mainArray[indexesMap.get(t2)].compareTo(mainArray[indexesMap.get(t1)]);
    }
}

主要内容:

String[] points = {"100", "500", "200", "400", "300"};
String[] countries = {"nepal", "japan", "finland", "brazil", "spain"};
Comparator<String> comparator = new CustomArrayComparator<String, String>(points, countries);
Arrays.sort(countries, comparator);
Arrays.sort(points, Collections.reverseOrder());

System.out.println(Arrays.toString(points));
System.out.println(Arrays.toString(countries));

输出:

[500, 400, 300, 200, 100]
[japan, brazil, spain, finland, nepal]