public Vertex noSuccessor() {

		Vertex noSuccessorVertex;
		for (int r = 0; r < ROWS; r++) {
			noSuccessorVertex = vertices[r];
			int noSuccessorColumn = r;
			for (int c = 0; c < COLS; c++) {
				if (graph[r][c] > 0) {
					noSuccessorVertex = null;
				}
			}
			if (noSuccessorVertex != null) {
				for (r = 0; r < ROWS; r++)
					graph[r][noSuccessorColumn] = 0;
				return noSuccessorVertex;
			}
		}
		return null;
	}