You need intuition in those problems.

To develop intuition, you have to practice. Record your thought process. If you can do the problem, take a look back what steps have you taken to get you there. If you cannot do the problem, compare what you've got and the editorial, and see what you are missing, Repeating this a lot of times will help you to know what to do soon after you see a problem.

Basically I would try out small cases, and see how well it generalizes. Then it would be some constant optimizations on the number of vertices needed.

I have not actually done the constant optimization part yet tho. I think it needs some clever way to optimize the number of vertices.

Literally just practice this is the 30520th question asking this. There is no shortcut. Practice

I agree that practice is the most important. The most important thing to train is your intuition and your pattern seeking abilities.

In a contest, you should try out small cases and see if you can spot some pattern that can be generalized. This is how you use your intuition and pattern seeking skill.

Sometimes the pattern you tried to conclude is wrong. Then try again. Constructive problems have a lot of trial and error.

he's the local farter in my locality he's a big bully he keeps bullying me i feel very sad every time i see him cuz i know he will grab me and throw me into a trash can :sob:

OMG SPARKY MASTER IS BACK, IS ALIVE!

MASTER PLEASE TEACH US YOUR WAY

I am a 15 year old Hong Kong student.

Can you first teach me how to get near perfect score in IMO on your first year?

Sadly no

Actually I do not think a newbie should learn tree dp yet. You should consolidate your basics first.

But anyways, dp is a tool to use when there are a lot of overlapping sub-problems. You should use the fact that the number of edges of a tree is linear and that there is no cycle to help the dp.

Just practice. Since your question is quite generic I cannot give you a concrete answer. You can scroll through other comments of mine here on this post to see some more advice.

1874D - Jellyfish and Miku

Not anytime soon

CP is so fun :)

Favorite OI problem that is public already? 1815E - Bosco and Particle

Favorite OI problem that is not yet public? I have one that I really like, will definitely use for my next round.

Favorite math problem? The following problem has a really elegant and elementary solution, you can try it out!

Let $$$ABCD$$$ be a rectangle. Let $$$E$$$ be on side $$$\overline{AB}$$$ such that $$$BE=6$$$, and let $$$F$$$ be the intersection of $$$\overline{AC}$$$ and $$$\overline{DE}$$$. If the distance from $$$F$$$ to side $$$\overline{AD}$$$ is $$$15$$$, and the absolute difference between the areas of $$$\triangle AEF$$$ and $$$\triangle CDF$$$ is $$$40$$$, what is the area of $$$BCFE?$$$

I think you should learn all the things you need for your skill level, solving a few example problems for each thing you learn. Then you solve problems of your rating to your rating plus 300. Do that until you can confidently solve those problems before moving on to new topics.

I think that Codeforces has a lot of good blogs on different DSA. Just search them up. I think it would not be hard to distinguish a high quality tutorial with a low quality one (you can look for the rating of the author). There will be some recommendations on what problems to solve on those blogs. The amount of problems you solve is not fixed, as I have said in the previous paragraph, solve until you feel confident in solving problems of a similar difficulty and the same trick in the future. In addition, if you have a coach, you can also ask him/her for assistance on what tricks to learn and what problems to solve.

You need to know !D and 2D partial sum and difference array, two pointers, binary search, and the built in data structures (stack, queue, priority_queue, deque, vector, map, set, multiset if you are using C++) and math stuff to reach specialist. Actually you only need those until Candidate Master.

I think an advice is that if you think you are exhausted, try taking a break from CP. This can help you recover, which will make you better.

Next is how to deal with contest stress (what you asked for). In a codeforces contest, if you are not doing well, just remind yourself that it is just a codeforces contest and you should not be too stressed about it. In a cp contest that actually matters, you should try to see how can you get the maximal score in the remaining time you have. If you are really stressed out drink some water and go to toilet to calm down.

That is all that I have!

Combinatorics and some equations involving floor, mod and bitwise operators. Look them up!

You do not need to know any algorithms and data structures except

• Partial sum, difference array (1D,2D)
• Basic built in data structures of your programing language
• Binary search, two pointers

You have to be good at making observations, and sometimes deriving formulas. That is why I recommend you to learn basic combinatorics and some identities about mod, floor, and bitwise operations.

So, just learn the above and you can start doing problems until you are confident to do all problems below expert. Then you can learn more advanced algorithms such as dp and algorithms about graph, and data structures like sparse table and segment tree. But bear in mind that you can reach Candidate Master with only the basic stuff that I mentioned.

Also when I read a book and encounter something that I do not understand, I will try to skip it first and read stuff that is not dependent on that thing I do not understand.

Hong Kong is a special administrative region of China

No I am just late to reply

You might see I rarely submit on codeforces except for contests.

This is because there is a online judge only for Hong Kong students and I usually do the problems there. Also, when I do problems on codeforces, I do the problems from mashups set by my school’s coach so you won’t be able to see it.

No, but I have participated in IMO 2023.

I believe that gift will affect how quick you can learn, but a gifted person must still learn and practice in order to become better. This applies in literally anything.

Sorry but I don’t know who’s gKaeni

Very important. Basically, the problems that you are able to solve is limited by your math ability.

Even in data structure problems, you have to come up with formulas. If you cannot do algebra correctly, you cannot solve the problem.

I have finished answering above questions.

I think arvindf232 is a better person to answer this question.