I have noted a glitch in the codeforces compiler leading to my failed on main test cases verdict. In the question B of this contest, whose link is this, my solution which passed on pretests is this

After running on main tests , it showed wrong answer on main tests 11 .

I checked the error and found it is giving wrong answer in this test case : 77921270569329490 377318254283917957 Its correct output is : 1005355647 while my code on codeforces compiler gave the output : 1005355648

I copied my code and ran it on every online compiler I know as well as my local compiler and everywhere it gave the correct answer, while in codeforces inbuilt compiler it gave wrong answer.

I tried to dig further in it and found that it is not even printing the square root of 77921270569329490 correctly (which is 279143817, but its giving 279143816), which is taken care in all other compilers.

This glitch lead my answer to fail in main test cases.

If the moderator is viewing this, please check my submission on different compiler or do something about it. I do not want my rating to go down for no reason while it could have gone up.

While doing problemsets on dp I came across this 1200 rated question whose name is 'Alternating Subsequence' and it was asked in codeforces round 636 , div 3 C. Question code is 1343 C and link to the problem is https://codeforces.net/problemset/problem/1343/C

In its third sample testcase the sequence given is -2 8 3 8 -4 -15 5 -2 -3 1 and we have to choose the maximum length alternating subsequence , which should be -15,5,-2 . But the answer given to it is according to subsequence -2 8 , which is not the longest subsequence and hence do not fulfill the requirements of question.

I checked the announcements and questions asked about this problem in live contest(which I did not give) , but couldn't find anything . And as a newbie , I don't know where to ask questions like this .

Please help me or guide me where can I ask and clarify my doubt.