The pre-processing strategies strive to efficiently aggregate multiple cookies into a collection of ``cookie groups," which it then delegates to one of the fundamental strategies described above. The reasoning we employ is that pre-processing an arrangement of 
cookies will produce an arrangement of 
groups, where is significantly less than (by at least a factor of 2), and that the fundamental placers can place a smaller number of cookies more efficiently than a larger number, since the depth of the search tree is proportional to the number of cookies.
To realize this, we implemented Cookie and CookieGroup according to the Composite design pattern, which allowed us to carry out any placement strategy on an arbitrary collection of cookies (see Implementation).