Nuts and bolts problem

//Nuts and bolts problem

import java.io.*;
import java.util.*;

public class Main {

    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int tc = Integer.parseInt(br.readLine().trim());

        while(tc-- > 0) {
            String[] inputLine;
            int n = Integer.parseInt(br.readLine().trim());
            char[] nuts = new char[n], bolts = new char[n];
            inputLine = br.readLine().trim().split(" ");

            for(int i = 0; i < n; i++) {
                nuts[i] = (inputLine[i].charAt(0));
            }

            inputLine = br.readLine().trim().split(" ");

            for(int i = 0; i < n; i++) {
                bolts[i] = (inputLine[i].charAt(0));
            }

            new Solution().matchPairs(n, nuts, bolts);

            for(int i = 0; i < n; i++) {
                System.out.print(nuts[i] + " ");
            }
            System.out.println();

            for(int i = 0; i < n; i++) {
                System.out.print(bolts[i] + " ");
            }
            System.out.println();
        }
    }
}

class Solution {
    void matchPairs(int n, char nuts[], char bolts[]) {
        char arr[] = { '!', '#', '$' , '%', '&', '*', '?', '@' , '^'};
        HashSet<Character> set = new HashSet<>();
        
        for(char ch : nuts) {
            set.add(ch);
        }
        
        int k = 0;
        
        for(int i = 0; i < arr.length; i++) {
            if(set.contains(arr[i])) {
                nuts[k] = arr[i];
                bolts[k] = arr[i];
                k++;
            }
        }
    }
}