Roman To Integer

var roman = {
    "I": 1,
    "V": 5,
    "X": 10,
    "L": 50,
    "C": 100,
    "D": 500,
    "M": 1000
};

var romanToInt = function(s) {
    if (s.length < 1) {
        return 0;
    }

    for (var i = s.length - 1; i >= 0; i--) {
        if (i == s.length - 1) {
            var res = roman[s[i]];
            continue;
        }

        if (roman[s[i]] >= roman[s[i + 1]]) {
            res += roman[s[i]];
        } else {
            res -= roman[s[i]];
        }
    }

    return res;
};