I know many people who didn't. Even myself, after ~1900 I didn't have a coach, only friends and acquaintances whom i could ask something.

I don't say that one doesn't need a coach to become div1, but having a coach absolutely is not a necessary condition to reach some certain level (at least up to read)

Neither I deny that with a good coach you will in fact most likely reach it sooner. However, if one is stuck at some point, I believe just something is wrong about his approach/attitude for trainings, and that's the first thing that has to be changed before getting a coach

It is certainly possible, I am not a CM but until very recently I had no friends that did CP. Everything I did, I did it 100% by myself.

I did get everywhere I am without having had any formal coaching besides having been introduced to C++ and the very basic algorithms, however I would have done it much faster if I had a coach or someone to mentor me throughout the process.

However, online communities such as Errichto's server are very useful and I've seen a lot of people improve over time as they learn from more experienced peers. Even back in the day when I used to be a more active competitor, being an active member in various discord servers was very helpful especially as far as making the step to more superior echelons of competitive programming, so yes, getting to purple is possible by yourself, however having someone to guide you can be very useful.

Master here. Trained all by myself since March this year with no coach but a few friends to discuss with.

it's certainly possible, I've seen a person who reached IM on their own, I myself reached CM without any sorts of coaching

I had a small amount of coaching when I was starting competitive programming (before I even knew codeforces existed) but for the last few years I've been self-guided. It's definitely possible to go from blue -> div1 without a coach, although as some people have mentioned I'd imagine it would be easier with one.

Actually coaches are useless. I mean yes it's good to ask seniors and high rated people how did they practice etc but more than that it's basically useless. You don't need someone to explain algorithms or stuff for you, you just need to solve and learn by yourself. It's good to have people to guide you, but in the end it comes down to practicing and self reliance

I will show you how to reach M just by myself, even without friends.

In fact if you want to become CM or Master,coach isn't necessary.

You can become expert by youself,why can't you become Master the same way?

Coach may help you get better grade faster,but you can also improve by youself as long as you are really hard-working.

Indeed, I'm one. Just a bunch of competitive friends and a will to improve are enough for CM imo.

i dont have a coach i reached newbie by my own determination and hardwork

Coaching shines whenever you feel that you've hit a wall. Everything else, like how to train, which algorithms to cover, which problems to select, etc is public information in the internet, already repeated by a lot of top coders.

So I would recommend coaching if you are feeling stuck (it doesn't really matter if you are stuck or not, whatatters is that you are FEELING stuck, and that will hinder your progress).

I think the best type of coaching you can get is through a training camp. You get curated problemsets, with analyais, meet new people, etc.

I just recently managed to do it, there's a lot of helpful stuff on the internet, just trust the process and have fun!!

The only people who like coaching are coaches. This truly says a lot about society.