public static Stack <List <int> > GetFillingSteps(INavigator navigator, LocationGroup locationGroup)
{
var result = new Stack <List <int> >();
var antiNavigator = navigator.ReplaceWithBoxes(locationGroup);
var scope = new Queue <INavigator>();
scope.Enqueue(antiNavigator);
while (scope.Count > 0)
{
var currentNavigator = scope.Dequeue();
var step = new List <int>();
foreach (var entryPoint in locationGroup.EntryPoints)
{
var boxesToExit = GetBoxesToExit(currentNavigator, entryPoint);
step.AddRange(boxesToExit.Except(step));
}
if (step.Count > 0)
{
var navigatorAfterStep = currentNavigator.Replace(step, Sokoban.LOCATION);
scope.Enqueue(navigatorAfterStep);
result.Push(step);
}
}
return(result);
}
public INavigator ReplaceWithBoxes(LocationGroup group)
{
var newMap = map.Replace(Sokoban.BOX, Sokoban.EMPTY)
.Replace(Sokoban.BOX_ON_LOCATION, Sokoban.LOCATION)
.Replace(Sokoban.KEEPER, Sokoban.EMPTY)
.Replace(Sokoban.KEEPER_ON_LOCATION, Sokoban.LOCATION);
var sb = new StringBuilder(newMap);
foreach (var location in group.Positions)
{
sb[location] = Sokoban.BOX_ON_LOCATION;
}
sb[group.EntryPoints[0].Position] = Sokoban.KEEPER;
return(new Navigator(Width, Height, sb.ToString()));
}
