LeetCode 13. 罗马数字转整数

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 -= hash[s[i]]; else res += hash[s[i]]; } return res; } };