Given a roman numeral, convert it to an integer.

Input is guaranteed to be within the range from 1 to 3999.

题目大意

给你个罗马数字，把它转换成一个int数。输入限定在[1, 3999]。

难度系数：容易

实现

一次性通过，：）

int getVal(char a)
{
    switch (a) {
    case ‘I‘:
        return 1;
    case ‘V‘:
        return 5;
    case ‘X‘:
        return 10;
    case ‘L‘:
        return 50;
    case ‘C‘:
        return 100;
    case ‘D‘:
        return 500;
    case ‘M‘:
        return 1000;
    }
    return 0;
}

int romanToInt(string s)
{
    int res = 0;
    char max = ‘I‘;
    for (int i = s.size()-1; i >= 0; --i) {
        if (getVal(s[i]) >= getVal(max)) {
            max = s[i];
            res += getVal(s[i]);
        } else {
            res -= getVal(s[i]);
        }
    }
    return res;
}

LeetCode13——Roman to Integer