Hi Codeforces,

We're excited to invite you to OI Contest #1, which will take place on [contest_time:388712]. All problems were created and prepared by MinaRagy06, zordeno, Adam.Aly, and 3omar_ahmed.

Thanks to our testers for their time and valuable feedback: PurpleCrayon, SlavicG, HossamHero7 and Omar_Fakhry.

The contest will be OI Style not CPC Style.

The contest will be 5 hours and you have 5 problems to solve them.

Hope to see you in the standing, wish you good luck.

UPD1: Registration opened for the contest.

In the last round in Educational Codeforces Round 130 (Rated for Div. 2) i solved awoo's Favorite Problem with complexity $$$O(N^2)$$$ by compiler GNU C++20 (64) i wonder how i didn't get TLE, I don't know if there is solution with complexity $$$O(N^2)$$$ or if the tests wasn't good in this problem, also i submited it with compiler GNU C++17 (64) and got accepted ,But i submited it with compiler GNU C++17 and got TLE (Time limit exceeded).

Submissions :

• GNU C++20 (64) : 160339878

• GNU C++17 (64) : 160486994

• GNU C++17 : 160487011

How does it happen ?? Why GNU C++17 (64) and GNU C++20 (64) is better than GNU C++17 ?? How my solution with complexity $$$O(N^2)$$$ works ??

thanks.