CSP techniques are useful in solving complex configuration and allocation problems. You are given the
task of allocating four developments in a new site in Queens. You have to place a housing complex, a big
hotel, a recreational area and a garbage dump. The area for development can be represented as 3x3
grid (three rows 0,1,2 and three columns 0,1,2) and you need to place each development in their own
cell of the grid. Unfortunately, there are some practical constraints on the problem that you need to
take into account. In the following, A is close to B if A is in a cell that shares an edge with B.