To design a local search algorithm for an optimization problem you have to define the following components:

1. candidate solution representation
2. evaluation function
3. initial solution
4. a neighborhood operator
5. step function
6. stopping criterion

After implementation and test of the above components, improvements in efficiency (ie, computation time) can be achieved by:

A. fast delta evaluation
B. neighborhood pruning
C. clever use of data structures

Improvements in quality can be achieved by:

D. application of a metaheuristic
E. definition of a larger neighborhood