一种用ArrayList方式的解法

先判断是否存在,再存入,最后排序输出:

 import java.util.Scanner;
import java.util.*;
public class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        int cnt = in.nextInt();
        int demo = 0;
        ArrayList<Integer> nums = new ArrayList<Integer>();
        for(int i = 0; i < cnt; i++){
            demo = in.nextInt();
            if(nums.contains(demo) == false)
            nums.add(demo);
        }
        nums.sort(Comparator.naturalOrder());
        for(int i : nums)
            System.out.println(i);
    }
}