Some solutions to atcoder problems will not get AC without optimization pragmas despite being optimal in time complexity:

Without pragmas: link

With pragmas: link

Hello, as I write this blog its about 30 minutes before the Codeforces Round 984 (Div. 3), and I think I found the bug possibly caused by incoming contest.

Go to this link

Go to "Past contests" section and below you will see links to different pages (example link to page 2)

It redirects me to this link instead.

I'm not sure if this is intended? If this is a known bug or intended feature please kindly inform me, I will delete this blog.

Hi codeforces community!

So I was solving this problem: 1703G - Хороший ключ, плохой ключ

I wrote first solution: 283940469 ~ TLE

I wrote second solution: 283940935 ~ AC

Two programs are very similar to each other so i will list most notable differences between them:

• First solution uses C-array a of size N = 1e5 defined globally. Second solution uses vector of size n which is defined for each test case
• First solution uses vector<vector<ll>> dp, with N rows and each row is of size 31 and for each test it fills every row with vector<ll>(31, -1). Second solution uses similar dp vector but has n rows and is defined in the solve function
• First solution accesses variables n, k, dp from the global scope. Second solution passes references to vectors as parameters and variable k also as parameters for each recursive call.

I sincerely thought first solution would be faster than second solution.

So, my question is why is that first solution gets TLE but second solution gets AC?