private static long Input()
{
var attempt = Attempts.Pop().Where(dir => !Visited.Contains(Compass.PositionAfterMovement(droidPosition, dir))).ToList();
if (attempt.Count == 0)
{
Backtracking = true;
Attempt = Compass.Opposite(EnteredFrom[droidPosition]);
}
else
{
Backtracking = false;
Attempt = attempt[0];
attempt.RemoveAt(0);
Attempts.Push(attempt);
}
var backTrackingString = Backtracking ? " (BACKTRACKING)" : "";
Day15Debug.Write($"({droidPosition.x}),{droidPosition.y}) - {Compass.Name(Attempt)}{backTrackingString} : ");
return(Compass.ToLong(Attempt));
}