JBMO TST Bosnia and Herzegovina 2022 P4
Source: JBMO TST Bosnia and Herzegovina 2022
May 21, 2022
JBMO TSTcombinatoricsnational olympiad
Problem Statement
Some people know each other in a group of people, where "knowing" is a symmetric relation. For a person, we say that it is if it knows at least other persons and at least of those know each other. For a person, we say that it is if it doesn't know at least other persons and at least of those don't know each other. Find the maximal number of people in that group, if we know that group doesn't have any nor persons.