long roadsAndLibraries(
    int const & citiesCount,
    int const & costLib, 
    int const & costRoad,
    std::vector<std::vector<int>> const & roads
){
    using namespace std;
    if(costLib <= costRoad){
        return static_cast<long>(citiesCount) * costLib;
    }
    auto citiesConnected{unordered_map<int, vector<int>>{}};
    for(auto const & road: roads){
        citiesConnected[road.at(0)].emplace_back(road.at(1)); 
        citiesConnected[road.at(1)].emplace_back(road.at(0)); 
    }
    auto citiesVisited{vector<bool>(citiesCount, false)};
    auto isolatedRegions{0};
    auto doBFS = [&](auto const & city){
        auto qBFS{queue<int>{}};
        qBFS.push(city);
        citiesVisited.at(city - 1) = true;
        while(!qBFS.empty()){
            for(auto const & neighbour: citiesConnected.at(qBFS.front())){
                if(citiesVisited.at(neighbour - 1)){
                   continue; 
                }
                qBFS.push(neighbour);
                citiesVisited.at(neighbour - 1) = true;
            }
            qBFS.pop();
        }
    };
    for(auto const & [city, _]: citiesConnected){
        if(citiesVisited.at(city - 1)){
            continue;
        }
        doBFS(city);
        ++isolatedRegions;
    }
    isolatedRegions += citiesCount - citiesConnected.size();
    return isolatedRegions * static_cast<long>(costLib) +
        (citiesCount - isolatedRegions) * static_cast<long>(costRoad);
}