#include <string>
#include <map>

typedef std::map<std::string, unsigned long> RomanNumeral;

class RomanToIntegerSolution {

    private:
        RomanNumeral numTable;

    public:
        int romanToInt(std::string s) {

            unsigned long roman(0);
            std::string remainder;
            remainder.resize(s.length());

            unsigned long singleRomanNumerals[255];

            singleRomanNumerals['I'] = 1;
            singleRomanNumerals['V'] = 5;
            singleRomanNumerals['X'] = 10;
            singleRomanNumerals['L'] = 50;
            singleRomanNumerals['C'] = 100;
            singleRomanNumerals['D'] = 500;
            singleRomanNumerals['M'] = 1000;

            numTable["IV"] = 4;
            numTable["IX"] = 9;
            numTable["XL"] = 40;
            numTable["XC"] = 90;
            numTable["CD"] = 400;
            numTable["CM"] = 900;

            auto len(s.length());
            unsigned long j(0);
            unsigned long i = 0;

            for ( ; i < len-1; i++ ) {
                char str[3];
                str[0] = s[i];
                str[1] = s[i+1];
                str[2] = 0;

                auto it(numTable.find(str));
                if (it != numTable.end()) {
                    roman += it->second;
                    i++;
                } else {
                    remainder[j++] = s[i];
                    remainder[j] = 0;
                }
            }
            if ( i < len ) {
                remainder[j++] = s[i];
                remainder[j] = 0;
            }
            for (i = 0; (i < remainder.length()) && (remainder[i] != 0); i++) {
                roman += singleRomanNumerals[remainder[i]];
            }

            return roman;
        }
};