我需要根据两个参数rankdist(嵌入式排序)对元素进行排序。首先,必须按降序对元素赋予rank值。其次,这些有序元素必须根据dist值以降序重新排序。

例:

rank = [8.0, 2.0, 8.0, 5.0, 2.0]
dist = [1.2, 2.2, 3.1, 1.1, 0.8]

Step 1: ordered rank = [8.0, 8.0, 5.0, 2.0, 2.0], indexes = [0, 2, 3, 4, 1]

Step 2: ordered dist = [3.1, 1.2, 1.1, 2.2, 0.8], indexes = [2, 0, 3, 1, 4]


因此,最终结果为indexes = [2, 0, 3, 1, 4]。想法是,在步骤2中,我们只能交换具有相同等级的元素。

我当前的代码版本如下:

public static void main(String[] args) {
    ArrayList<Double> rank = new ArrayList<Double>();
    rank.add(8.0);
    rank.add(2.0);
    rank.add(5.0);
    rank.add(1.0);
    rank.add(2.0);
    rank.add(8.0);

    ArrayList<Double> dist = new ArrayList<Double>();
    dist.add(1.8);
    dist.add(2.8);
    dist.add(1.1);
    dist.add(2.1);
    dist.add(2.2);
    dist.add(1.5);

    ArrayList<ArrayList<Double>> result = new ArrayList<ArrayList<Double>>();
    result.add(0,rank);
    result.add(1,dist);

    System.out.println(result.get(0));

    ArrayList<Double> nstore1 = new ArrayList<Double>(result.get(0));
    Collections.sort(result.get(0));
    int[] indexes1 = new int[result.get(0).size()];
    for (int n = 0; n < result.get(0).size(); n++){
        indexes1[n] = nstore1.indexOf(result.get(0).get(result.get(0).size()-n-1));
    }
    System.out.println(Arrays.toString(indexes1));

}


我陷入了第2步。在考虑排名顺序的同时,如何使元素受dist的重新排序?任何直观的示例将不胜感激。

最佳答案

import java.util.Arrays;

public class SortObject {

    public static void main(String args[]) {

        Student[] students = new Student[4];

        Student one = new Student(8.0, 1.8);
        Student two = new Student(2.0, 2.8);
        Student three = new Student(5.0, 1.1);
        Student four = new Student(1.0, 2.1);

        students[0] = one;
        students[1] = two;
        students[2] = three;
        students[3] = four;

        // Arrays.sort(students, Student.StudentComparator); // to sort on basis
        // of both rank and dist

        Arrays.sort(students);

        int i = 0;
        for (Student temp : students) {
            System.out.println("fruits " + ++i + " : " + temp.getRank()
                    + ", Quantity : " + temp.getDist());
        }

    }
}


复制并尝试这个。并且让我知道它可以解决问题。

import java.util.Comparator;

public class Student implements Comparable<Student> {

    private Double rank;
    private Double dist;

    public Student(double rank, double dist) {

        this.rank = rank;
        this.dist = dist;

    }

    public Double getRank() {
        return rank;
    }

    public Double getDist() {
        return dist;
    }

    public int compareTo(Student student) {

        return (int) (student.rank - this.rank);

    }

    public static Comparator<Student> StudentComparator = new Comparator<Student>() {

        public int compare(Student student1, Student student2) {

            Double first = student1.dist;
            Double second = student2.dist;

            return (int) (second - first);

        }

    };
}

10-07 19:15
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