MathDB
Maximum number of flights in a country

Source: 2021 Turkey JBMO TST P3

May 24, 2021
combinatoricscombinatorics proposed

Problem Statement

In a country, there are 2828 cities and between some cities there are two-way flights. In every city there is exactly one airport and this airport is either small or medium or big. For every route which contains more than two cities, doesn't contain a city twice and ends where it begins; has all types of airports. What is the maximum number of flights in this country?