Communication tasks are an interesting subset of the category of non-batch tasks, and are usually found in olympiads infrequently (for example IOI 2011 Parrots). Recently, some of my friends and I wanted to hold a contest for fun for our school and wanted to write a communication task. May I ask, how (if possible) can it be implemented on codeforces/polygon platform? Is there a checker sample/template that I can use as reference? Thanks.