remove method

VertexList remove(Vertex vertex)

Implementation

VertexList remove(Vertex vertex ) {
	if ( vertex.prev == null ) {
		head = vertex.next;
	}
    else {
		vertex.prev?.next = vertex.next;
	}

	if ( vertex.next == null ) {
		tail = vertex.prev;
	}
    else {
		vertex.next?.prev = vertex.prev;
	}

	vertex.prev = null;
	vertex.next = null;

	return this;
}