题解 | #输入整型数组和排序标识，对其元素按照升序或降序进行排序#

一开始的思路是使用TreeMap, 有序不允许重复
代码写出来了, 但是有的案例不通过, 估计是案例中重复的输入被自动去重了.

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner ip = new Scanner(System.in);
        int length = Integer.valueOf(ip.nextLine());
        String in = ip.nextLine();
        int id =  Integer.valueOf(ip.nextLine());

        String[] arr = in.split(" ");
        TreeSet<Integer> treeSet = new TreeSet<Integer>();
        for (int i = 0; i < (length); i++){
            treeSet.add(Integer.valueOf(arr[i]));
        }
        Iterator<Integer> it =
                (id==1?(((TreeSet)treeSet.descendingSet())):treeSet)
                        .iterator();
        while(it.hasNext()){
            System.out.print(it.next()+" ");
        }
    }
}

那我只好使用ArrayList了,简单修改了一下通过了, 就是代码有点丑

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner ip = new Scanner(System.in);
        int length = Integer.valueOf(ip.nextLine());
        String in = ip.nextLine();
        int id =  Integer.valueOf(ip.nextLine());

        String[] arr = in.split(" ");
        List<Integer> list = new ArrayList<>();
        for (int i = 0; i < (length); i++){
            list.add(Integer.valueOf(arr[i]));
        }
        list.sort(null);
        if (id == 0){
            for (Integer e: list){
                System.out.print(e+" ");
            }
        }else {
            for (int i = list.size()-1; i>=0; i--){
                System.out.print(list.get(i)+" ");
            }
        }

    }
}