Step 3: Add a new constraint which passes through B and parallels the objective function.
Use original constraints and this new constraint to form two subspaces.
These two subspaces are both smaller than original solution space and we label the area near A as the target subspace.
Step 4: Searching for integer optimum solution using B&B procedure in this target subspace. If we can obtain
the integer optimum solution, then terminate and claim that this is the optimum point. If the integer
optimum solution is not found in this subspace, then return to step 2 to continue looking for the next
nearest subspace. Stop after the result is found.