There are two types of professional wrestlers: "babyfaces" ("good guys") and "heels" ("bad guys"). between any pair of professional wrestlers, there may or may not be a rivalry. suppose we have n professional wrestlers and we have a list of r pairs of wrestlers for which there are rivalries. give an o.n c r/-time algo- rithm that determines whether it is possible to designate some of the wrestlers as babyfaces and the remainder as heels such that each rivalry is between a babyface and a heel. if it is possible to perform such a designation, your algorithm should produce it.