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