Crozzle: an NP-complete problem

At the 1996 Symposium on Applied Computing, it was argued that the R-by-C Crozzle problem was NP-Hard, but not in NP. The original Crozzle problem is a word puzzle that appears, with a cash reward for the highest score, in The Australian Women’s Weekly. The R-by-C Crozzle problem generalizes the original. We argue that both problems are, in fact, NP-Complete. This follows from the reduction of exact 3-set cover to R-by-C Crozzle and the demonstration of a non-deterministic polynomial time algorithm for solving an arbitrary instance of the R-by-C Crozzle problem. A Java implementation of this algorithm is also considered. ∗supported in part by National Science Foundation grant CCR-9411861

• Type: Conference
• Year: 1997
• Where: SAC
• Authors: David Binkley, Bradley M. Kuhn
• Keywords: Applied Computing, Crozzle Problem, Original Crozzle Problem, R-by-C Crozzle Problem, SAC 1997