13. 罗马数字转整数

 1 class Solution 
 2 {
 3 public:
 4     int a[13] = {1,4,5,9,10,40,50,90,100,400,500,900,1000};
 5     vector<string> b = {"I","IV","V","IX","X","XL","L","XC","C","CD","D","CM","M"};
 6 public:
 7     int romanToInt(string s) 
 8     {
 9         int res = 0;
10         for(int i = 0;i < s.size();)
11         {
12             string str = s.substr(i,2);
13             auto it = find(b.begin(),b.end(),str);
14             if(it != b.end()) 
15             {
16                 res += a[it - b.begin()];
17                 i += 2;
18             }
19             else
20             {
21                 string str;
22                 str.push_back(s[i]);
23                 auto iter = find(b.begin(),b.end(),str);
24                 res += a[(iter - b.begin())];
25                 i++;
26             }
27         }
28         return res;
29     }
30 };