[Java] [Java] Method for inexperienced person to become paizaB rank in 2 weeks

6 minute read


Our training for new employees is “While doing self-learning, ask senior engineers what they don’t understand.” It is a style, but as a temporary intermediate goal, it was set to take B rank by Paiza’s skill check. I have reached B rank in about 2 weeks from a state of inexperience and almost no knowledge, so I will summarize what I learned. Capture 254.PNG


However, B rank of paiza is not particularly great. Even if you answer the B-rank problem once, the rank will go up, so even an inexperienced person like me can get it. Just because the rank is B, it’s hard to say that you can solve other problems easily, and I honestly don’t think that it reflects the current level of ability. In the first place, the training is to acquire the basic knowledge and skills necessary for work, so Paiza’s rank is just a guide.

However, if you can solve the C-rank problem reasonably well and reach the B-rank, it’s far better than you don’t know anything. In fact, by setting some goals and learning, I was able to feel growth.

at least ・It can be used properly by combining multiple if statements, for statements, and while statements. ・Understand the movement of operators and write code ・Can create and operate arrays without problems ・Can convert int type and String type ・You can use equals and == ・Simple methods such as substring and split can be used

  • You can read the desired value or character string using standard input.

I think that the basics of the basics of java, such as above, can be acquired naturally.

content of study

If you are new to full-scale programming, you may be worried whether you can do it. In fact, I was also worried whether I could get B rank during the training period. However, no matter how bad you swallow it, you can reach it if you learn it step by step.

Day 1 ~ Day 2 Get an overview by installing Progate or Dot

Those who are not working but self-learning are likely to have already done it, but first, let’s get an overview of the language with Progate etc. What is programming? At that level, let’s understand it.

It’s important to note that you don’t spend too much time here. As many engineers say, do not run Progate for weeks because it is meaningless even if you challenge the skill check.

For Progate, java courses 1 to 3 are enough. It’s important to get an overview, so you don’t have to practice.

Day 2 Learn standard input and challenge D rank problem

After learning to some extent, you should try D rank immediately, but Paiza’s problem is that “Read value using standard input” is necessary, and even if you do not understand this, even D can be solved. can not. First, let’s use standard input. Java standard input commentary paiza Learning [Java] Paiza’s skill check will be blocked by D if you can not use standard input

I think you can understand it in half a day. After that, let’s try D rank.

In the skill check, the scores are sorted in ascending order, so if you are confused about which problem to try, you can definitely choose from the top (choose the lower one for higher difficulty).

There is nothing so difficult, so I think you can clear the D rank.

Days 3 to 5 Challenge D and C ranks while inputting in paiza learning

Next is C rank, but as expected, if you do some Progate, there is still concern about knowledge, so let’s do paiza learning. There are 10 courses in all, but I think that 1 to 6 are enough. Even if D rank could not be cleared at the stage of the previous day, if you supplement your knowledge here, you should be able to answer correctly. After that, I will try C rank. If you are a complete beginner, even if you have enough knowledge, you may not be able to express it well in the program and it will lead to a time up, but let’s do it seriously. I think I’m used to this area.

I solved about 40 D-rank problems and then tried C-rank, but I don’t have to do that. Let’s quickly go to the C-rank problem.

Day 6 ~ Day 10 Solve C rank problem and B rank level up set

In the contents of paiza, there is a B rank level up set composed of D and C. You may try this if you have a hard time with the C rank problem. I solved all the questions, but if I didn’t understand it, I looked at the answer code. Capture 255.PNG

If you can answer about 10 C-rank questions in a timely manner, proceed to the next step.

After that ~ Challenge the B rank problem

If you do this, I think that a simple B-rank problem will be sufficient in terms of knowledge. It is necessary to think about the logic, but except for some problems, you can basically solve it by combining if and for statements. Try about 5 questions and if you don’t understand any, go back to C. If you can get the correct answer, you can aim for A rank or S rank, or you can go to Atcoder and train at a higher level place.

Tips when you are likely to be frustrated

The speed of growth is different for each person

People who originally programmed in high school or university even if they have no practical experience, or those who are appropriate may reach B rank in 2 days a day instead of 2 weeks. However, the speed of growth varies from person to person, so don’t be impatient. If you go straight, you will definitely get it at the latest. When you are tired, you can take a short break.

It is important to think for yourself and write

Most of the problems of paiza are “make a program that works like OO”. The conditional branch here needs to be actually written by considering whether to branch under this condition with an if statement. By repeating it, you can increase the number of drawers in your head and deal with various problems. Obviously, I haven’t studied “thinking and not actually writing”, so let’s stop doing it aimlessly (for example, taking notes in a notebook is meaningless).

Don’t try to write cleanly, but give priority to what you expect.

The model answers of the exercises and the code that comes out by searching the net are beautiful and beautiful. However, when you are a beginner, let’s give priority to “Can you write with the knowledge that you know the behavior you expect?” For the time being, I’ll explain how you can write a short method using a method. Even if the code is messed up, if I can somehow solve the problem using if and for statements, I think it’s good now. However, if possible, it is best to have your seniors and superiors review.

Use if you can listen

In my case, it was part of the training of the company, so it was an environment where I could ask questions to senior engineers, but I regret that I didn’t ask so many questions. If you have a listening environment, use it. However, I was able to solve about 90% by doing my own research, so I think that there is no problem in self-study.


I am currently studying to improve myself, but I was worried many times during my studies whether I could really improve my skills properly. I think that if you work with tenacity, you will be able to overcome it, so I would be happy if it would be helpful and helpful for beginners who are also learning.