I see a lot of coding contests hosted in lots of sites like,codeforces,codechef,Atcoder,etc. But what i need is online Math contests where a person solves math problems and can look for the editorial for learning new techniques just like coding contests. Are there any possible sites available for Math contests??

https://codeforces.com/contest/1792/problem/D

//At the bottom there is my submission.

https://codeforces.com/contest/1792/submission/190984642

can anyone help me in giving further ideas to optimize my implementation. If possible can anybody teach me how to tackle these kinds of problems with newer ideas(new concepts).

I started coding after I discovered some of the problem setter's cp journey, so thank you, all the problem setters for making wonderful problems. Because of you guys every week we give wonderful contests.

what are the good books suggested to master combinatorial thinking. I would appreciate if anyone recommends me good books on combinatorial thinking. please share your experiences on your combinatorial learning so far.

I don't get any idea on how to choose a problem that could teach you some concept. Recently I am struggling with 1100 rated problems. I am usually not able to solve any question of this category during the contest. By applying tags is also not helping me. What should I do next in order to improve??

How to remove $$ sign and make formulas and numbers visible??