public boolean hasEdge(int start, int end)
    {
        if (start < 0 || start >= myNumVertices || end < 0 || end >= myNumVertices) {
            return false;
        }
        for (Edge e : myEdges[start]) {
            if (e.getTarget() == end) {
                return true;
            }
        }
        return false;
    }