[剑指offer] 2. 替换空格

class Solution
{
public:
  void replaceSpace(char *str, int length)
  {
    int spaceNUms = 0;
    for (int i = 0; i < length; i++)
    {
      if (str[i] == ‘ ‘)
      {
        ++spaceNUms;
      }
    }

    for (int j = length - 1; j >= 0; j--)
    {
      if (str[j] != ‘ ‘)
        str[j + 2 * spaceNUms] = str[j];
      else
      {
        --spaceNUms;
        str[j + 2 * spaceNUms] = ‘%‘;
        str[j + 2 * spaceNUms + 1] = ‘2‘;
        str[j + 2 * spaceNUms + 2] = ‘0‘;
      }
    }
  }
};