public int [] compute_indegree() {
private int [] compute_indegree() {
	public int [] compute_indegree() {		int [] indeg = new int[_graph.numVertices()];		for(int i = 0; i < _graph.numVertices(); i++) {			indeg[i] = _vtx_index_tbl[i].inEdges().size();		}		return indeg;	}