题目链接:https://leetcode-cn.com/problems/roman-to-integer/
题目如下:
class Solution {
public:
int romanToInt(string s) {
unordered_map<char,int> umap={
{'I',1},
{'V',5},
{'X',10},
{'L',50},
{'C',100},
{'D',500},
{'M',1000},
};
int res=0;
int n=s.size();
for(int i=0;i<n;i++){
if(i<n-1&&umap[s[i]]<umap[s[i+1]]){
res-=umap[s[i]];
}else{
res+=umap[s[i]];
}
}
return res;
}
};