all longest strings

std::vector<std::string> allLongestStrings(std::vector<std::string> a) {
    std::vector<std::string> r;
    int b=0;
    for(int i=0; i<a.size(); i++){
        if(a[i].length()>b) b=a[i].length();
    }
    for(int i=0; i<a.size(); i++){
        if(a[i].length()==b) r.push_back(a[i]);
    }
    return r;
}