/// <summary>
/// Expands both path searches until they intersect, and returns the path.
/// Returned path is from the source of the first search to the source of the second search.
/// </summary>
public List <CPos> FindBidiPath(PathSearch first, PathSearch second)
{
while (first.CanExpand && second.CanExpand)
{
// make some progress on the first search
var p = first.Expand();
var pInfo = second.Graph[p];
if (pInfo.Status == CellStatus.Closed &&
pInfo.CostSoFar != PathGraph.PathCostForInvalidPath)
{
return(MakeBidiPath(first, second, p));
}
// make some progress on the second search
var q = second.Expand();
var qInfo = first.Graph[q];
if (qInfo.Status == CellStatus.Closed &&
qInfo.CostSoFar != PathGraph.PathCostForInvalidPath)
{
return(MakeBidiPath(first, second, q));
}
}
return(NoPath);
}
/// <summary>
/// Expands the path search until a path is found, and returns that path.
/// Returned path is *reversed* and given target to source.
/// </summary>
public List <CPos> FindPath(PathSearch search)
{
while (search.CanExpand)
{
var p = search.Expand();
if (search.IsTarget(p))
{
return(MakePath(search.Graph, p));
}
}
return(NoPath);
}