leetcode.13---------Roman to Integer

Given a roman numeral, convert it to an integer.

Input is guaranteed to be within the range from 1 to 3999.

请参考上一篇博文：

<a target=_blank href="http://blog.net/chenxun_2010/article/details/43274049">http://blog.csdn.net/chenxun_2010/article/details/43274049</a>

roman to int:

class Solution {
public:
  inline int map(const char c) {
    switch (c) {
    case 'I': return 1;
    case 'V': return 5;
    case 'X': return 10;
    case 'L': return 50;
    case 'C': return 100;
    case 'D': return 500;
    case 'M': return 1000;
    default: return 0;
    }
  }
  int romanToInt(string s) {
    int result = 0;
    for (size_t i = 0; i < s.size(); i++) {
      if (i > 0 && map(s[i]) > map(s[i - 1])) {
        result += (map(s[i]) - 2 * map(s[i - 1]));
      }
      else {
        result += map(s[i]);
      }
    }
    return result;
  }
};