In this paper, we will propose a universal relation between the holographic
complexity (dual to a volume in AdS) and the holographic entanglement entropy
(dual to an area in AdS). We will explicitly demonstrate that our conjuncture
hold for all a metric asymptotic to AdS3, and then argue that such a
relation should hold in general due to the AdS version of the Cavalieri
principle. We will demonstrate that it holds for Janus solution, which have
been recently been obtained in type IIB string theory. We will also show that
this conjecture holds for a circular disk. This conjecture will be used to show
that the proposal that the complexity equals action, and the proposal that the
complexity equal volume can represent the same physics. Thus, using this
conjecture, we will show that the black holes are fastest computers, using the
proposal that complexity equals volume.Comment: 15 pages, Major revisio