LeetCode/Roman_to_integer.cpp at main · Sushil-19/LeetCode · GitHub

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class Solution {
public:
    int value(char r)
        {
            if (r == 'I')
                return 1;
            if (r == 'V')
                return 5;
            if (r == 'X')
                return 10;
            if (r == 'L')
                return 50;
            if (r == 'C')
                return 100;
            if (r == 'D')
                return 500;
            if (r == 'M')
                return 1000;

            return -1;
        }
    int romanToInt(string str) {
        int res = 0;
        for (int i = 0; i < str.length(); i++)
        {
            int s1 = value(str[i]);
            if (i + 1 < str.length())
            {
                int s2 = value(str[i + 1]);
                if (s1 >= s2)
                {
                    res = res + s1;
                }
                else
                {
                    res = res + s2 - s1;
                    i++;
                }
            }
            else {
                res = res + s1;
            }
        }
        return res;
    }
};