National High School Programming Contest 2020 - National Round
This contest has ended. It had started on and ran for 4 hours 30 minutes.
You can use C++11 GCC 7.4, C++14 GCC 8.3, C++17 GCC 9.2, C11 GCC 9.2, and 4 other programming languages PyPy 7.1 (2.7), PyPy 7.1 (3.6), Python 2.7, and Python 3.7 in this contest.
Be fair, be honest. Plagiarism will result in disqualification. Judges’ decisions will be final.