hello, i'm wondering how to confirm if a user that seems suspicious is a cheater (obviously theres no way to be sure, but just to be more confident). i saw apersonref's preformance on the last contest (div3), getting a WA1 on A, failing to solve E, and im not sure if im correct in calling them a cheater. if anyone has better advice in how to spot cheaters, would you be open to telling me? just what are some general signs and stuff?