To stay purple the best is not to take part in Div1 contest :)

To stay purple your rating will be in the interval [1700; 1900).

You can check yourself what place approximately you need to get to stay purple or to increase your rating. In order to do that you need to look into Div1 contest and find some guy with rating similar to yours and see how his results affected his rating.

For example let's look into the latest contest standings (official only!). If you filter out unofficial participants you will see that on the 5-th page people were solving only the easiest problem. You can see there are a lot of purple guys there. I looked into this guy results for example. You can see that he solved 1 problem, took 411 place and his rating didn't change much. So you can deduce that to stay purple it's enough to solve ~1 problem.

That being said it's only an average. It will depend on whether you will always solve exactly one problem or you will solve 0-2 problems being more unstable. Of course every round is different on its own but there is still a point here, you can focus on different things — either looking into a lot of new topics which will give you a chance to solve a lot of problems sometimes of focus on coding correctly the problems you really know how to solve even if you will have no clue how to solve more complicated problems.

I find it really hard to stay in Div 1. My advice is: Don't get disappointed even if you go back to Div 2! Lol As for ranking, you can just virtual-participate and see ratings of ppl who got similar scores.

Practice more. Also, up-solving is very important. There is no way without up-solving. :)

As they say the best defense is offense go for red and maybe you will stay purple and not fall to blue!

It depends on problem difficulties.

Usually, one fast solved problem is enough to stay purple. By solving two problems fast, you can become master or even international master. :)

Also, hacks are very important. Try to hack more, because 5 hacks = A full score. I saw a one guy whose solution failed systests, but he got a new international master rank because of +17 hacks :D

Practice & practice!

Congrats bro :))

Congrats for being purple :)