Tim Floyd resigned Tuesday as the men's basketball coach at the University of Southern California, as accusations continued to swirl that he broke rules in the recruitment of O.J. Mayo, who played one year at USC before bolting for the National Basketball Association in 2008. Floyd has denied the allegation that he paid $1,000 to an associate of Mayo referred to in news reports as his "handler," and his resignation letter said he had lost "enthusiasm" for the job. But in announcing his resignation, Southern California officials said that the university is "cooperating fully in the continuing investigation" into rules violations, and that "no conclusions have yet been reached."