fligths among 2023 cities
Source: (2022-) 2023 XVI 16th Dürer Math Competition Finals Day 2 E13
May 25, 2024
combinatorics
Problem Statement
A country has cities and there are flights between these cities. Each flight connects two cities in both directions. We know that you can get from any city to any other using these flights, and from each city there are flights to at most other cities. What is the maximum possible number of cities in the country from which there is a flight to only one city?