题目
Given a roman numeral, convert it to an integer.
Input is guaranteed to be within the range from 1 to 3999.
频度： 4
解题之法
class Solution {
public:
int romanToInt(string s) {
unordered_map<char, int> T = { { 'I' , 1 },
{ 'V' , 5 },
{ 'X' , 10 },
{ 'L' , 50 },
{ 'C' , 100 },
{ 'D' , 500 },
{ 'M' , 1000 } };
int sum = T[s.back()];
for (int i = s.length() - 2; i >= 0; --i)
{
if (T[s[i]] < T[s[i + 1]])
{
sum -= T[s[i]];
}
else
{
sum += T[s[i]];
}
}
return sum;
}
};
