There am 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 + r)-time algorithm

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.

subject: design and analysis of algoritm

in case of algorithm code use c++