Duplicated Numbers (10分)

6-14 Duplicated Numbers (10分)

This program reads a lot of integers, in which may be duplicated numbers. The program picks out all the duplicated ones and sorts the remainders in a descendent order.

函數接口定義：

public static ArrayList<Integer> pick(ArrayList<Integer> a);

a is the ArrayList to be parsed and returns the result as an ArrayList.

裁判測試程序樣例：

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.Scanner;

public class Main {
    /* 請在這裏填寫答案 */

    public static void main(String[] args) {
        ArrayList<Integer> lst = new ArrayList<>();
        Scanner in = new Scanner(System.in);
        while ( in.hasNextInt() ) {
            lst.add(in.nextInt());
        }
        lst = pick(lst);
        for ( int x:lst) {
            System.out.print(x+" ");
        }
        System.out.println();
        in.close();
    }
}

輸入樣例：

1 1 2 3 4 5 9 3

輸出樣例：

9 5 4 3 2 1 

public static ArrayList<Integer> pick(ArrayList<Integer> a)    {
        ArrayList<Integer> rs = new ArrayList<Integer>();
        for(int i=0;i<a.size();i++) {    
            if(!rs.contains(a.get(i))) {
                rs.add(a.get(i));
            }
        }
        Collections.sort(rs);
        Collections.reverse(rs);
        return rs;
    }