Hello Codeforces, I have a habit of checking others solutions after the contests, to get an idea about different approaches. However sometimes I see someone's every submission during the contest getting skipped. Although they have got a positive delta , but their submission is 0. What does it mean or why this happens? Can someone please tell or suggest relevant blog posts. Thankyou.

I am trying to submit a solution, but it is in queue for a long time and I am not able to know whether my solution is right or not.

finally, after 6 months and 23 days I'm green. Jai Shree Ram

I was recently trying to solve problem 230B - T-primes and I'm getting WA on test 8, I don't know why. Also the solution comes out correct in my local compiler. I need help. attaching the solution. 244541266

I have solved quite a few A and B in practice but I'm not able to solve them in contests. Suggest me ways to improve. I want to be green!