A Tabled Prolog Program for Solving Sokoban

This paper presents our program in B-Prolog submitted to the third ASP solver competition for the Sokoban problem. This program, based on dynamic programming, treats Sokoban as a generalized shortest path problem. It divides a problem into independent subproblems and uses mode-directed tabling to store subproblems and their answers. This program is very simple but quite efficient. Without use of any sophisticated domain knowledge, it easily solves 14 of the 15 instances used in the competition. We show that the approach can be easily applied to other optimization planning problems.