13. Roman to Integer（LeetCode）

Given a roman numeral, convert it to an integer.

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

class Solution {
public:
       map<char, int> m;
    int romanToInt(string s) {
    m.insert(pair<char, int>('I', 1));
    m.insert(pair<char, int>('V', 5));
    m.insert(pair<char, int>('X', 10));
    m.insert(pair<char, int>('L', 50));
    m.insert(pair<char, int>('C', 100));
    m.insert(pair<char, int>('D', 500));
    m.insert(pair<char, int>('M', 1000));
    map<char, int>::iterator ite;
    int len = s.size();
    char current;
    char pre;
    int temp = 0;
    int result=0;
    pre = s[0];
    temp = m[pre];
    for (int i = 1; i<s.size(); i++)
    {
        current = s[i];
        if (m[current]==m[pre])
        {
            temp += m[current];
        }
        else
        {
            if (m[current] > m[pre])
            {
                temp = m[current] - temp;
            }
            else
            {
                result += temp; 
                temp = m[current];
            }
        }    
        pre = current;
    }
    return result+temp;
    }
    
};