Simplify Path leetcode

string simplifyPath(string path) {
    string str;
    vector<string> strs;
    stringstream ss(path);
    while (getline(ss, str, ‘/‘))
    {
        if (str == "." || str == "")
            continue;
        else if (str == "..") {
            if (!strs.empty())
                strs.pop_back();
        }        
        else
            strs.push_back(str);
    }
    string ret;
    for (auto s : strs)
        ret += "/" + s;
    return ret.empty() ? "/" : ret;
}