Hello codeforces !

in my college they want me to speak about a successful website or
company or idea ...... so i chose codeforces i want your help in this blog to answer this questions:

1- why codeforces is successful or special from your point of view ?

2 — what is the thing you think if it exist in codeforces it will be better ?

3- MikeMirzayanov , please tell us the story how you start this brilliant website ?

at the last "Div 2" round i sent solution for problem B but i get Wrong answer on test 2 ....I spend a lot of time try to discover why my idea is wrong?!! actually my idea and my code was true , but because (sqrt function do not work in GNU 20 with long long number and same function work with GNU 17 i get wrong answer and my rate will decrase more than 150 point,** so please if you know some issues like this, please type it in the comment to know it , especially in differences between these two compilers**

my code AC on GNU 17 , WA on GNU 20

https://mirror.codeforces.com/contest/1809/submission/198835668

https://mirror.codeforces.com/contest/1809/submission/198811956