public Iterable<WeightedDirectedEdge> pred(int v)
	{
		List<WeightedDirectedEdge> pred = new LinkedList<>();
		for (int i = 0; i < V(); i++)
		{
			for (WeightedDirectedEdge e : adj(i))
				if (e.to() == v)
					pred.add(e);
		}
		return pred;
		
	}