public static HashSet <Vec2i> BFS_ReachableNodes_MaximumSteps(
this PM_Maze maze,
Vec2i root,
bool includeRoot,
int maximumSteps
)
{
// start the bfs search...
Dictionary <Vec2i, Vec2i> predecessors = new Dictionary <Vec2i, Vec2i>();
Dictionary <Vec2i, int> numSteps = new Dictionary <Vec2i, int>();
var allNodes = maze.CellsPositions_All_List();
//T dummyNode = T.Dummy();
foreach (var node in allNodes)
{
predecessors.Add(node, node);
numSteps.Add(node, int.MaxValue);
}
HashSet <Vec2i> visited_Nodes = new HashSet <Vec2i>()
{
root
};
Queue <Vec2i> searchQueue = new Queue <Vec2i>();
searchQueue.Enqueue(root);
numSteps[root] = 0;
while (searchQueue.Count > 0)
{
var current = searchQueue.Dequeue();
if (numSteps[current] < maximumSteps)
{
HashSet <Vec2i> unvisitedNeighbors = maze.Cells_Connected_To_Cell__Set(current);
unvisitedNeighbors.ExceptWith(visited_Nodes);
foreach (var neighbor in unvisitedNeighbors)
{
predecessors[neighbor] = current;
numSteps[neighbor] = numSteps[current] + 1;
searchQueue.Enqueue(neighbor);
visited_Nodes.Add(neighbor);
}
}
}
HashSet <Vec2i> reachable_within_steps = new HashSet <Vec2i>();
foreach (var node in visited_Nodes)
{
if (numSteps[node] <= maximumSteps)
{
reachable_within_steps.Add(node);
}
}
if (includeRoot)
{
return(reachable_within_steps);
}
else
{
reachable_within_steps.Remove(root);
return(reachable_within_steps);
}
}
