题解 | #整型数组合并#

import java.util.*;

// TreeSet
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int x = in.nextInt();
        TreeSet<Integer> set = new TreeSet<>();
        for (int i = 0; i < x; i++) {
            set.add(in.nextInt());
        }
        int y = in.nextInt();
        for (int i = 0; i < y; i++) {
            set.add(in.nextInt());
        }
        int size = set.size();
        for (int i = 0; i < size; i++) {
            System.out.print(set.pollFirst());
        }
    }
}