public Iterator<E> minimumSpanningTree() {
		DirectedGraph cc = new DirectedGraph(size);
		List<E>[] mstList = cc.lists;
		int nbrOfNotConnected = size;
		PriorityQueue<CompKruskalEdge<E>> kruskPq = new PriorityQueue<CompKruskalEdge<E>>();
		for(List<E> tmpList: lists){
			for(E ex: tmpList){
				kruskPq.add(new CompKruskalEdge<E>(ex));
			}
		}
		while(!kruskPq.isEmpty() && nbrOfNotConnected > 1){
			CompKruskalEdge<E> e = kruskPq.poll();
			if(!(mstList[e.getFrom()] == mstList[e.getTo()])){
				List<E> longestList = mstList[e.getFrom()];
				List<E> shortestList = mstList[e.getTo()];

				if(shortestList.size() > longestList.size()){
					List<E> tmpList = shortestList;
					shortestList = longestList;
					longestList = tmpList;
				}

				for(E f: shortestList){
					longestList.add(f);
				}
				longestList.add(e.getEdge());
				for(E g: shortestList){
					mstList[g.from] = longestList;
					mstList[g.to] = longestList;
				}
				mstList[e.getFrom()] = longestList;
				mstList[e.getTo()] = longestList;
			}
		}

		return mstList[0].iterator();
	}
}