Generalized TSS and its optimization

In several sorts of games, such as Connect6, Renju, or Go-moku, etc., when sequences of consecutive forced moves appeared, TSS (Threat Space Search) could be adopted to find one of such sequences if existed. TSS is inspired from the process of chess master´s pondering on that condition. In some ways, sequences of forced moves are so popular that we can use it to deal with a family of games effectively, named k-in-a-row. So, we propose a generalized algorithm, DFID-TSS, where we apply the strategy of DFID (Depth First Iterative Deepening) into TSS (Threat Space Search). Without loss of the generality, we also propose some optimized rules, by which lots of branches of the proving tree may be terminated earlier. At last, the results show that DFID-TSS is robust, adaptive, and efficient.