Usually, red coders speedrun A, B very fast while I'm still having trouble reading the statement, and most of the time I found that they're even more annoying to code than C, D, E even thought they're easier. Is it because those problems have appeared frequently and red coders have solved all of them before ?

Hi everyone, lately I have been struggle in atcoder. It's not that I want to complaint or anything but something I just feel off. If it was codeforces problems then even if it's 3500 difficult problem, I can solve most of them given enough time and think hard enough, but I don't feel like it with atcoder. So someone with experience can tell me what diffirent about it ? Thanks in advance

Lately I've been submitted codes to Building Skyscrapers. You don't have to understand my code but to better explanation, my first idea is to use unordered set and map to reduce first half of the solutions to $$$O(N)$$$ but it got TLE : 57946506. I've managed to submit again and get 100pt just by get rid of the ordered set (still use the unordered map) and running time reduce from > 3500ms to 2589 ms : 57994251. Finally, I get rid of both of them and just sort the whole vector and use the two pointer in $$$O(NlgN)$$$, the time reduced to 655 ms : 58085217.

I believed there is something wrong with the default hash function. Can anyone improve it ?

GCJ platform 2018 Is this site closed ? Can anyone access it ?

Recently I've been submited some pratice code to solve the Edgy Baking problem of Google code jam but there always are some error in my output, even thought the difference never exceed 0.01 as I've tested some random input. Can someone please check it ? https://pastebin.com/526V81qR