题目：

题解：

class Solution {
private:unordered_map<char, int> symbolValues = {{'I', 1},{'V', 5},{'X', 10},{'L', 50},{'C', 100},{'D', 500},{'M', 1000},};public:int romanToInt(string s) {int ans = 0;int n = s.length();for (int i = 0; i < n; ++i) {int value = symbolValues[s[i]];if (i < n - 1 && value < symbolValues[s[i + 1]]) {ans -= value;} else {ans += value;}}return ans;}
};