A Nice Graph Theory Problem from the 2022 China IMO Team Selection Test

Searching for Eulerian cycles 🚲

At the International Mathematical Olympiad, China is the undisputed world leader and superpower. Of the last 20 IMOs, China has won 1st place 13 times, 2nd place 5 times and 3rd place twice.

So it makes sense that questions from the China IMO Team Selection Tests are often more challenging than the actual IMO questions. But this graph theory question from the 2022 test is not super-hard. It is super-nice though… enjoy!