static void Main()
{
CitiesMapParseResult parseResult = CitiesMapParser.Parse("in.txt");
(long start, long end, CitiesMap map) = (parseResult.StartCity, parseResult.EndCity, parseResult.Map);
MinDistanceResult result = map.GetMinDistance(fromCity: start, toCity: end);
Console.WriteLine(result.MinDistance);
Console.WriteLine(result.Path);
}
public MinDistanceResult GetMinDistance()
{
if (_result != null)
{
return(_result);
}
_heap.Add(new CityDistance(_fromCity, _fromCity, 0));
while (!_minDistanceCities.Contains(_toCity))
{
CityDistance currentCity = _heap.Pop();
long currentCityIndex = currentCity.To;
if (currentCity == null)
{
return(MinDistanceResult.NotFound());
}
_minDistanceCities.Add(currentCityIndex);
var roadsFromCurrentCity = _distanceMap.GetRoadsFromCity(currentCityIndex);
foreach (var(toCity, distance) in roadsFromCurrentCity)
{
long newDistance = distance + currentCity.Distance;
long currentMinDistance = _distancePathByCityNumber.ContainsKey(toCity)
? _distancePathByCityNumber[toCity].Distance
: long.MaxValue;
if (newDistance < currentMinDistance)
{
_heap.Add(new CityDistance(currentCityIndex, toCity, newDistance));
_distancePathByCityNumber[toCity] = new DistancePath(newDistance, currentCityIndex);
}
}
}
_result = new MinDistanceResult(
_distancePathByCityNumber[_toCity].Distance,
GetMinPath());
return(_result);
}