public static AdjListNode[] genRandomUndirectedGraph(int vertexCount) {
		if(vertexCount <= 0) {
			return null;
		}
		
		AdjListNode[] graphList = new AdjListNode[vertexCount];
		Random random = new Random();
		for(int i=0;i<vertexCount;i++) {
			if(graphList[i] == null) {
				graphList[i] = new AdjListNode(String.valueOf(i));
			}
			for(int j=0;j<i;j++) {
				if(random.nextBoolean()) {
					if(graphList[j] == null) {
						graphList[j] = new AdjListNode(String.valueOf(j));
					}
					graphList[i].adjacencies.add(graphList[j]);
					graphList[i].edgesWeight.add(1);
					graphList[j].adjacencies.add(graphList[i]);
					graphList[j].edgesWeight.add(1);
				}
			}
		}
		return graphList;
	}