0013 Roman To Integer

• Simple
• C++

问题概述

解题思路

class Solution
{
public: 
    int romanToInt(std::string s)
    {
        int sum = 0;
        for (int i = 0; i < s.length(); i++)
        {
            if (i + 1 < s.length() && GetValue(s[i]) < GetValue(s[i + 1]))
            {
                sum += GetValue(s[i + 1]) - GetValue(s[i]);
                i++;
            }
            else
            {
                sum += GetValue(s[i]);
            }
        }
        return sum;
    }

private:
    int GetValue(char ch)
    {
        int value = 0;
        switch (ch)
        {
        case 'I': value = 1; break;
        case 'V': value = 5; break;
        case 'X': value = 10; break;
        case 'L': value = 50; break;
        case 'C': value = 100; break;
        case 'D': value = 500; break;
        case 'M': value = 1000; break;
        default:
            break;
        }
        return value;
    }
};

class Solution
{
public:
    std::map<char, int> RomanIntMap = {
        {'I', 1},
        {'V', 5},
        {'X', 10},
        {'L', 50},
        {'C', 100},
        {'D', 500},
        {'M', 1000}
    };

    int romanToInt(std::string s)
    {
        int sum = 0;
        for (int i = 0; i < s.length(); i++)
        {
            if (i + 1 < s.length() && RomanIntMap[s[i]] < RomanIntMap[s[i + 1]])
            {
                sum += RomanIntMap[s[i + 1]] - RomanIntMap[s[i]];
                i++;
            }
            else
            {
                sum += RomanIntMap[s[i]];
            }
        }
        return sum;
    }
};