Police at SUU (Small Unnamed University) have got the report that the student was skateboarding in hall. They rush to scene of crime to find who guilty party is, and they are met by 3 students: Alan, Bernard, and Charlotte. When asked, Alan says, "If Bernard didn't do it, then it was Charlotte." Bernard says, "Alan and Charlotte did it together or Charlotte did it alone." Charlotte says, "We all did it together."
i) If police know that exactly 1 person committed crime, and exactly one person is lying, find who is guilty party?
ii) As it turns out, exactly 1 person committed crime and all students are lying. Find who is guilty party?