leetcode第13题--Roman to Integer

Problem：

Given a roman numeral, convert it to an integer.

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

遍历一次输入的字符串，如果不满足类似4或者9的就直接加相应的数，否则减去相应的数。其中对应如下”IVXLCDM“对应{1,5,10,50,100,500,1000}

class Solution {

public:
int romanToInt(string s)
{
    string refe = "IVXLCDM";
    int val[] = {1, 5, 10, 50, 100, 500, 1000};
    int result = 0;

    for (int i = 0; i < s.size(); i++)
    {
        for (int j = 0; j < refe.length(); j++)
        {
            if (i+1<s.size() && s[i] == refe[j] && ((j+1<refe.size() && s[i+1] == refe[j+1]) || (j+2<refe.size() && s[i+1] == refe[j+2])))
            {result -= val[j];}
            else if (s[i] == refe[j])
            {result += val[j];}
        }
    }
    return result;
}
};