1.题目
2.代码
class Solution {
public:
int romanToInt(string s) {
int res = 0;
unordered_map<char, int> m{{'I', 1}, {'V', 5}, {'X', 10}, {'L', 50}, {'C', 100}, {'D', 500}, {'M', 1000}};
for (int i = 0; i < s.size(); ++i)
{
int val = m[s[i]];
if (i == s.size() - 1 || m[s[i+1]] <= m[s[i]])
res += val;
else
res -= val;
}
return res;
}
};