comefrom: <qiyuangong>066_Plus_One_1.java
code: private int[] addToDigit(int[] digits, int index) {
              if (index == -1) {
                  int[] newDigits = new int[digits.length + 1];
                  newDigits[0] = 1;
                  for (int i = 0; i < digits.length; i++) {
                      newDigits[i + 1] = digits[i];
                  }
                  return newDigits;
              }
              if (digits[index] == 9) {
                  digits[index] = 0;
                  return addToDigit(digits, index - 1);
              } else {
                  digits[index]++;
                  return digits;
              }
          }
masked: private int [ ] sample_funcname ( int [ ] digits , int index ) {
    if ( index == - 1 ) {
      int [ ] newDigits = new int [ digits . length + 1 ] ;
      newDigits [ 0 ] = 1 ;
      for ( int i = 0 ;
      i < digits . length ;
      i ++ ) {
        newDigits [ i + 1 ] = digits [ i ] ;
      }
      return newDigits ;
    }
    if ( digits [ index ] == 9 ) {
      digits [ index ] = 0 ;
      return addToDigit ( digits , index - 1 ) ;
    }
    else {
      digits [ index ] ++ ;
      return digits ;
    }
  }
  