Enhancing Planning Heuristic with Landmarks

Recently, landmarks count heuristic can increase the number of problem instances solved and improve the quality of the solutions in satisfying non-optimal planning. In order to make landmarks count heuristic optimal, we give the solution to the overestimate of landmarks count heuristic. We extend landmarks count heuristic without action cost assignments, and prove that the extension of heuristic is admissible. Our empirical evaluation shows that the extension of heuristic is admissible and can be competed with the state-of-the-art of heuristic.