(UVA) Decoding - Solution

Link to the problem: https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=738&page=show_problem&problem=2536


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

class Main {
    public void process() throws NumberFormatException, IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

        int numTests = Integer.parseInt(br.readLine());
        for (int test = 0; test < numTests; test++) {
            bw.write("Case " + (test+1) + ": ");
            String s = br.readLine();
            StringBuilder sb = new StringBuilder();
            int index = 0;
            while (index < s.length()) {
                char caracter = s.charAt(index);
                int number = 0;
                for(index = index + 1; index < s.length() && Character.isDigit(s.charAt(index)); index++) {
                    number = number*10 + (s.charAt(index)-'0');              
                }
                for (int i = 0; i < number; i++) {
                    bw.write(caracter);
                }
            }

            bw.write("\n");
        }
                                             
        bw.flush();
        bw.close();
      
        return;
    }
  
    public static void main(String[] args) throws NumberFormatException, IOException {
        Main m = new Main();
        m.process();
      
        System.exit(0);
    }
}