[백준/JAVA] 2675번 문자열 반복

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

class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        int t = Integer.parseInt(br.readLine());
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < t; i++) {
            StringTokenizer st = new StringTokenizer(br.readLine(), " ");

            int r = Integer.parseInt(st.nextToken());
            String s = st.nextToken();
            for (int j = 0; j < s.length(); j++) {
                for (int k = 0; k < r; k++) {
                    sb.append(s.charAt(j));
                }
            }
            sb.append("\n");
        }
        System.out.println(sb);
    }
}