利用TreeSet的有序性、无重复性:

import java.util.*;
public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        Set<Integer> v = new TreeSet<>();
        int n = sc.nextInt();
        while (sc.hasNext()) v.add(sc.nextInt());
        for(Integer i : v) System.out.printf("%d ", i);
    }
}