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;
};