For challenges which consist of two adversary (and asymmetric) sub-challenges.
For challenges which consist of two adversary (and asymmetric) sub-challenges:
- One is to produce valid answers which are as "good" as possible by some criterion (the cops)
- The other is to invalidate (or crack) existing answers (the robbers)
The winners will be the best answer to the former challenge that cannot be invalidated as well as the person who invalidated most submissions.
Consider posting a separate challenge for the robbers, such that submissions for this task can be properly explained and formatted (which might not be possible in comments). Robbers should be encouraged to link to the cop submission they are cracking, and to leave a comment on the cop submission linking to their robbers' answer.
In cases where invalidating an answer is possible computationally (e.g. in cryptography-based challenges), it is a good idea to set a time limit after which answers are safe (a week usually works well as a time limit).