private static List <Road> BFS(Road from, Road to)
{
Queue <Road> queue = new Queue <Road>();
HashSet <Road> explored = new HashSet <Road>();
Dictionary <Road, Road> parents = new Dictionary <Road, Road>();
queue.Enqueue(from);
while (queue.Count > 0)
{
Road current = queue.Dequeue();
if (current == to)
{
break;
}
RoadArray links = GetLinks(current);
for (int i = 0; i < links.Length; i++)
{
Road link = links[i];
if (!explored.Contains(link))
{
explored.Add(link);
parents.Add(link, current);
queue.Enqueue(link);
}
}
if (queue.Count == 0)
{
return(null);
}
}
List <Road> path = new List <Road>();
Road curr = to;
try
{
while (curr != from)
{
path.Add(curr);
curr = parents[curr];
}
path.Add(from);
path.Reverse(); // ?
return(path);
}
catch (KeyNotFoundException)
{
return(null);
}
}
private static RoadArray GetLinks(Road current)
{
RoadArray array = new RoadArray(4);
if (current.north != null)
{
array.Add(current.north);
}
if (current.south != null)
{
array.Add(current.south);
}
if (current.east != null)
{
array.Add(current.east);
}
if (current.west != null)
{
array.Add(current.west);
}
return(array);
}
