protected Problem(ProblemStats stats, IReadOnlyCollection <City> cities, List <Item> items)
{
Stats = stats;
CityIds = cities.Select(city => city.Id).ToList();
InterCityDistances = BuildInterCityDistances(cities);
Items = items;
}
protected Problem(ProblemStats stats, List <int> cityIds, Dictionary <CityCity, double> interCityDistances,
List <Item> items)
{
Stats = stats;
CityIds = cityIds;
InterCityDistances = interCityDistances;
Items = items;
}