백준 2675번: 문자열 반복

문제출처: https://www.acmicpc.net/problem/2675

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
 
public class Main {
    
    public static void main(String[] args) throws Exception {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        int T = Integer.parseInt(reader.readLine());
        StringBuilder builder = new StringBuilder();
        
        for(int i=0 ; i<T ; i++){
            StringTokenizer tokenizer = new StringTokenizer(reader.readLine());
            int R = Integer.parseInt(tokenizer.nextToken());
            String str = tokenizer.nextToken();
            
            for(int j=0 ; j<str.length() ; j++){
                for(int k=0 ; k<R ; k++){
                    builder.append(str.charAt(j));
                }
            }
            builder.append("\n");
        }
        
        System.out.println(builder);
    }
}