我需要根据两个参数rank
和dist
(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);
}
};
}