title: Remainder 7 Large Numbers
signature: function remainder7LargeNumbers($num) {
source_py: def remainder_7_large_numbers(num):
      series = [1, 3, 2, (- 1), (- 3), (- 2)]
      series_index = 0
      result = 0
      for i in range((len(num) - 1), (- 1), (- 1)):
          digit = (ord(num[i]) - 48)
          result += (digit * series[series_index])
          series_index = ((series_index + 1) % 6)
          result %= 7
      if (result < 0):
          result = ((result + 7) % 7)
      return result
source_cpp: int remainder_7_large_numbers(string num) {
    int series [ ] = {
      1, 3, 2, - 1, - 3, - 2 };
      int series_index = 0;
      int result = 0;
      for ( int i = num . size ( ) - 1;
      i >= 0;
      i -- ) {
        int digit = num [ i ] - '0';
        result += digit * series [ series_index ];
        series_index = ( series_index + 1 ) % 6;
        result %= 7;
      }
      if ( result < 0 ) result = ( result + 7 ) % 7;
      return result;
    }