#### Another Constraint Satisfaction Example

Federal Express needs to deliver four packages a,b,c, and d at one
of four times, 1,2,3, or 4. Let A represent the time at which a is
delivered, B represent the time at which b is delivered, etc. The
initial possible values for each delivery is the set {1, 2, 3, 4}.
The following constraints need to be met:
(B &ne 3) ^ (C &ne 2) ^ (A &ne B) ^ (B &ne C) ^ (C < D) ^ (A = D)^ (B &ne D)

If you applied backtracking search to this, how would the
search tree develop (consider the variables/values in
sorted order).

How would using the following change the search?

Most constrained variable
Most constraining variable
Least constraining value
Forward-checking search