public void removeEdge(String src, String dest) {
        Vertex v = vertexMap.get(src);
        int index = 0;
        for (Edge e : v.adj) {
            Vertex w = e.dest;
            int index2 = 0;
            if (w.name.equals(dest)) {
                for (Edge ew : w.adjEntering) {
                    if (ew.src.name.equals(src)) {
                        break;
                    }
                    index2++;
                }
                if (!w.adjEntering.isEmpty()) {
                    w.adjEntering.remove(index2);
                }
                break;
            }
            index++;
        }
        if (!v.adj.isEmpty()) {
            v.adj.remove(index);
        }
    }