I know that one should learn to debug oneself and learn to find the problems in their code. I am sorry to ask if this is not the right place.

https://codeforces.net/contest/1625/submission/178473012

I have been trying for long, to find where the problem might be, googled (for possible reasons of runtime errors — but similar answers — like insufficient memory or bugs — but where, I could not find), I could not find where the mistake is, maybe because I am inexperienced. Any help would be great.

Maybe there's something wrong in the erase — remove lines but I do not know. Also though I am still a beginner I somehow got to know about the erase and remove algorithms in STL (from a cpp course) and started using them after somewhat understanding their working. As a beginner, I should focus on solving simpler problems first, effectively, but I could not help it in the contest, I used whatever I knew, and was thrilled that I got an idea for problem C, when I did not even give about 5 contests.

(Also the large gap between january (contest date) and now is due to college, I forgot codeforces for a while until nowadays)

https://codeforces.net/contest/1625/submission/178473012

Thank you.