LeetCode 13: Roman to Integer

Roman to Integer

Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999.

解题思路

关于罗马数字的表示规则请参考Integer to Roman。

代码如下：

class Solution {
private:
    int getInt(char roman) {
        switch (roman) {
            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;
        }
    }
public:
    int romanToInt(string s) {
        int sum = 0;
        int slen = s.length();
        for (int i = 0; i < slen; ++i) {
            int v = getInt(s[i]);

            bool add = true;
            if (i < slen - 1 && (v < getInt(s[i+1]))) {
                add = false;
            }

            sum += (add ?  v : -v);
        }
        return sum;
    }
};