Pakkaus

import java.util.Scanner;

/**
 *
 * @author Miro Petsalo
 */
public class Compresio12n {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) { 
       Scanner s = new Scanner(System.in);
     String c = s.nextLine();
     int nb2 =c.length();
  
     StringBuilder answer1 = new StringBuilder("");
     String d[] = c.split("(?<=\\D)(?=\\d)|(?<=\\d)(?=\\D)");
int v4= d.length;
int f = -2;
      int df =-1;

  while (v4>0) { 
     
      
      int i=0;
     f=f+2;
    df=df+2;
       
      
        int x = Integer.parseInt(d[f]);
     
        while(x>0){
          answer1.append(d[df]);
            x=x-1;
         
                                            }

     
  
        
      v4=v4-2;
      
                                                    }
      System.out.println(answer1);   
    }
    
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED