Singleton arc consistency based on failure-first principle

Constraint satisfaction problems play a significant role in the field of Artificial Intelligence. Reducing the search space can improve the efficiency of solving the problems before the search of solutions. Applying in preprocessing step, arc consistency technique can remove some values which are arc inconsistent, so that it can reduce the search space. Using heuristic strategies can improve the efficiency of the algorithms. In this paper we propose a new singleton arc consistency algorithm based on failure-first principle, which improves the practical time efficiency through the earlier detection of variables which contain null values and removal of the values which are arc inconsistency during the preprocessing step.