private static IEnumerable <int> FindPath(Galaxy galaxy, int start, int end)
{
//start a heap the size of the galaxy
PQ pq = new PQ(galaxy.Size);
//distance array to each star
float[] distances = new float[galaxy.Size];
int[] previous = new int[galaxy.Size];
distances[start] = 0;
for (int i = 0; i < galaxy.Size; i++)
{
if (i != start)
{
distances[i] = Mathf.Infinity;
}
pq.AddWithPriority(i, distances[i]);
}
bool searching = true;
while (searching)
{
var currentSearchingIndex = pq.GetLowest().value;
SolarSystem currentSolarSystem = galaxy.solarSystems[currentSearchingIndex];
for (int i = 0; i < currentSolarSystem.linkedSystemIndex.Count; i++)
{
int otherIndex = currentSolarSystem.linkedSystemIndex[i];
float newDistance = distances[currentSearchingIndex] + currentSolarSystem.links[otherIndex].Distance;
if (newDistance < distances[otherIndex])
{
distances[otherIndex] = newDistance;
previous[otherIndex] = currentSearchingIndex;
pq.DecreasePriority(otherIndex, newDistance);
}
}
searching = !pq.IsEmpty() && distances[end] > pq.Peek().priority;
}
var sequence = new Stack <int>();
int target = end;
while (target != start)
{
sequence.Push(target);
target = previous[target];
}
return(sequence);
}