process.java

  for(int i = 0; i < arr.length; i++){
    long number = arr[i];
    int[] digits = new int[6];
    
    for(int j = 0; j < 6; j++){
      digits[i] = number % 10;
      number = number / 10;
    }
  
    arr[i] = (digits[0] + digits[5]) * 10000
      + (digits[1] + digits[4]) * 100
      + (digits[2] + digits[3]);
  }