Java 通过Index(索引)数组同时对多个数组进行排序

示例代码：

int[] indexes = new int[]{0,2,8,5};
String[] sources = new String[]{"how", "are", "today", "you"};
String[] targets = new String[]{"I", "am", "thanks", "fine"};

实现效果：

indexes -> {0,2,5,8}
sources -> {"how", "are", "you", "today"}
targets -> {"I", "am",  "fine",  "thanks"}

根据indexes对这三个数组进行排序

1、使用比较器Comparator

import java.io.*;import java.util.*;class Test {public static String[] sortWithIndex (String[] strArr, int[] intIndex )    {     if (! isSorted(intIndex)){        final List stringList = Arrays.asList(strArr);        Collections.sort(stringList, Comparator.comparing(s -> intIndex[stringList.indexOf(s)]));        return stringList.toArray(new String[stringList.size()]);       }     else        return strArr;    }public static boolean isSorted(int[] arr) {    for (int i = 0; i < arr.length - 1; i++) {        if (arr[i + 1] < arr[i]) {            return false;        };    }    return true;}       // Driver program to test function.    public static void main(String args[])    {        int[] indexes = new int[]{0,2,8,5};        String[] sources = new String[]{"how", "are", "today", "you"};        String[] targets = new String[]{"I", "am", "thanks", "fine"};           String[] sortedSources = sortWithIndex(sources,indexes);        String[] sortedTargets = sortWithIndex(targets,indexes);        Arrays.sort(indexes);        System.out.println("Sorted Sources " + Arrays.toString(sortedSources) + " Sorted Targets " + Arrays.toString(sortedTargets)  + " Sorted Indexes " + Arrays.toString(indexes));    }}

输出：

Sorted Sources [how, are, you, today] Sorted Targets [I, am, fine, thanks] Sorted Indexes [0, 2, 5, 8]

2、使用Lambda表达式

import java.io.*;import java.util.*;public class Test {public static String[] sortWithIndex (String[] strArr, int[] intIndex )    {  if (! isSorted(intIndex)) {        final List stringList = Arrays.asList(strArr);        Collections.sort(stringList, (left, right) -> intIndex[stringList.indexOf(left)] - intIndex[stringList.indexOf(right)]);        return stringList.toArray(new String[stringList.size()]);  }  else     return strArr;    }public static boolean isSorted(int[] arr) {    for (int i = 0; i < arr.length - 1; i++) {        if (arr[i + 1] < arr[i]) {            return false;        };    }    return true;}  // Driver program to test function.public static void main(String args[]){    int[] indexes = new int[]{0,2,5,8};    String[] sources = new String[]{"how", "are", "today", "you"};    String[] targets = new String[]{"I", "am", "thanks", "fine"};       String[] sortedSources = sortWithIndex(sources,indexes);    String[] sortedTargets = sortWithIndex(targets,indexes);    Arrays.sort(indexes);    System.out.println("Sorted Sources " + Arrays.toString(sortedSources) + " Sorted Targets " + Arrays.toString(sortedTargets)  + " Sorted Indexes " + Arrays.toString(indexes));}

3、使用List和map实现

import java.util.*;import java.lang.*;import java.io.*;public class Test{    public static > void sortWithIndex( final List key, List... lists){        if(key == null || lists == null)            throw new NullPointerException("Key cannot be null.");        for(List list : lists)            if(list.size() != key.size())                throw new IllegalArgumentException("All lists should be of the same size");        // 列表的大小为0或1，不需要排序        if(key.size() < 2)            return;        // 创建索引列表        List indices = new ArrayList();        for(int i = 0; i < key.size(); i++)            indices.add(i);        // 根据键对索引列表进行排序        Collections.sort(indices, new Comparator(){            @Override public int compare(Integer i, Integer j) {                return key.get(i).compareTo(key.get(j));            }        });        Map swapMap = new HashMap(indices.size());        List swapFrom = new ArrayList(indices.size()),                      swapTo   = new ArrayList(indices.size());        // 创建允许按N个交换对列表排序的映射。        for(int i = 0; i < key.size(); i++){            int k = indices.get(i);            while(i != k && swapMap.containsKey(k))                k = swapMap.get(k);            swapFrom.add(i);            swapTo.add(k);            swapMap.put(i, k);        }        // 使用交换顺序通过交换元素对每个列表进行排序        for(List list : lists)            for(int i = 0; i < list.size(); i++)                Collections.swap(list, swapFrom.get(i), swapTo.get(i));    }    public static void main (String[] args) throws java.lang.Exception{      List index = Arrays.asList(0,2,8,5);      List sources = Arrays.asList("how", "are", "today", "you");      // 列表类型不需要相同      List targets  = Arrays.asList("I", "am", "thanks", "fine");      sortWithIndex(index, index, sources, targets);      System.out.println("Sorted Sources " + sources + " Sorted Targets " + targets  + " Sorted Indexes " + index);    }}

输出：

Sorted Sources [how, are, you, today] Sorted Targets [I, am, fine, thanks] Sorted Indexes [0, 2, 5, 8]