Java离散化，根据类的某个成员排序数组

SortAndCompressArray.java

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) throws FileNotFoundException {
        int t;
        Scanner cin;

        FileInputStream fin;
        fin = new FileInputStream("/Users/liu/Hack/algorithm/spoj/INVCNT/src/input.txt");

        cin = new Scanner(fin);
//        cin = new Scanner(System.in);

        t = cin.nextInt();

        while (t-- != 0) {
            int n;
            Point[] a;

            n = cin.nextInt();
            a = new Point[n];

            for (int i = 0; i < n; ++i) {
                a[i] = new Point();
                a[i].value = cin.nextInt();
                a[i].pos = i + 1;
            }

            Arrays.sort(a);

//            compress y
            for (int i = 0; i < n; ++i) {
                a[i].compressValue = i + 1;
            }

            Arrays.sort(a, Point.PosComparator);
        }
    }

    static class Point implements Comparable  {
        int value;
        int pos;
        int compressValue;

        public static Comparator<Point> PosComparator = new Comparator<Point>() {
            public int compare(Point o1, Point o2) {
                return o1.pos - o2.pos;
            }
        };

        @Override
        public int compareTo(Object o) {
            return this.value - ((Point) o).value;
        }
    }
}