LeetCode 13. Roman to Integer

描述

解决

class Solution {
public:
int romanToInt(string s) {
unordered_map<char, int> arr;
arr['I'] = 1;
arr['V'] = 5;
arr['X'] = 10;
arr['L'] = 50;
arr['C'] = 100;
arr['D'] = 500;
arr['M'] = 1000;
int lenth = s.size();
int sum = 0;
for (int i = 0; i < lenth; ++i){
if (i != 0){
if (arr[s[i]] > arr[s[i - 1]]){
sum = sum - 2 * arr[s[i - 1]] + arr[s[i]];
}
else{
sum += arr[s[i]];
}
continue;
}
sum += arr[s[i]];
}
return sum;
}
};