【Participation experience & experience】
Let me introduce myself first. I participated in the C/C++B group. The competition area I am in is the Jiangsu competition area. I have participated in the Blue Bridge Cup three times.
There are generally three types of questions in the Blue Bridge Cup provincial competition: fill-in-the-blank, fill-in-the-blank and program questions, but the tenth session has no fill-in-the-blank questions. Fill-in-the-blank questions only need results, so as long as you can get the results out by non-illegal means, it's ok. Generally, only the last fill-in-the-blank question will be difficult, and the rest are easy to answer. However, from the real questions over the years, we can also see that the number of fill-in-the-blank questions is decreasing, and the number of procedural questions is increasing. Since the number of procedural questions is increasing, we must also pay attention to it, so naturally we cannot go to the examination room without knowing any algorithms. I basically mark the relevant algorithms in the problem solving table. It can be seen that the Blue Bridge Cup is the most common. The exam is still search algorithms, such as dfs and bfs, (I will not mention the too basic algorithms such as enumeration and recursion) My classmates often joke that the Blue Bridge Cup can win prizes as long as you know violence and search hhhhh so basic Algorithms still have to be known, you can focus on practicing search algorithms. Students who can learn more can continue to study more difficult algorithms, such as dynamic programming. Personally, I feel that the proportion of dynamic programming ideas in the Blue Bridge Cup is also increasing. I always think that the pit point of the Blue Bridge Cup is that you don't get a response after you submit it, that is, you don't know if you have AC after you submit the code, so you must pay attention to check the details before submitting. Program questions are scored according to the percentage of tested samples. If you can't think of a perfect AC solution, you can solve a part of the data scale first. If you really don't know this question, you can also first Violence, I hope I can pass a little test sample. Anyway, it's better than empty~ Finally, let's talk about the time issue. The whole game is 4 hours. It is recommended to browse the questions first, because although the questions are based on the difficulty gradient , but you don't know which question you will suddenly get stuck on, and you don't know which question you will suddenly have a flash of light. I often struggle with a question, so the questions I will do later are too late to finish the QAQ
Some friends worry that the competition area is different, so the experience I said has no reference value, but in fact, I want to say that this is not the case. When I first started participating in the competition, I also searched a lot of relevant information on the Internet, and the situation in other competition regions was similar. I personally think that competition is a competition at a level. Although there are a few people from the upper level and the lower level mixed in, most of them are still at the same level. Otherwise, what would you say about the competition? And because of the pitfalls of the Blue Bridge Cup, you don't know whether your code is right or wrong after you submit it, and you can't bring paper materials such as algorithm templates into it, so even if some students are good at programming, there is no absolute advantage. Of course, they are excellent. except. The friends who have done the real questions can also see that the difficulty of the Blue Bridge Cup questions is increasing year by year, and the proportion of programming questions is also increasing. I said before that it is enough to do a good job of filling in the blanks, but now there are some filling-in-the-blank questions that are not so good. It's easy to do, but you won't be able to do all of the programming questions, so to summarize again, if you do fill-in-the-blank questions, you may get more points for programming questions. Speaking of the changes in the real questions, I also want to mention that I personally feel that the Blue Bridge Cup involves more and more algorithms. Provincial competitions focus on basic algorithms, and national competitions focus on advanced algorithms. Although the two ranges of basic algorithms and advanced algorithms are very It is wide, but I intend to count the specific algorithms and frequencies that appear in it. You can also know that there are basically only a few of the exams, but in recent years, there have been more and more people who have not taken the exam. I mean more, don't be nervous, or For the minority, the reason for mentioning this here is that students who want to learn more and want to win prizes can broaden the algorithm for brushing questions later.
【Review suggestion】
1. Students who are beginners in programming:
At this time, most students will encounter such a situation. When I see the question, I have some ideas, but I can't write it. I searched the Internet for the solution, and I can understand it after reading it, but I still can't write it. This problem is my own My younger brothers and sisters have also asked me many times, and I myself was like this when I started. Because you are just starting out, your programming ability at this time is not enough for you to complete a problem by yourself, so it is better to borrow from others generously. Write down the code you can think of first, no matter how much, and then continue to write with reference to other people's code. If you forget or get stuck after reading it, look back at other people's, and then complete your own code. Don't fight to the end by yourself, or completely copy other people's code (that is, the screen is divided into two, one is yours and the other is someone else's, and then copying is like practicing typing)! Of course, you can't think that doing this once, you will know it all. Believe it or not, you will forget it after a few days. When starting out, brushing questions is not about the number of questions, but the number of repetitions. Brush it two or three times, and you can almost memorize it. At this time, the code you write is completely yours~
2. Students participating for the first time:
Personally, I feel that when Lanqiao first started to prepare, he still had to brush the real questions first to understand the situation. I also list the algorithms involved in each question in the problem solving table. It is not difficult to see that the algorithms that are often tested include enumeration (violence), recursion, greed, search (dfs and bfs) and other basic algorithms, and the basic algorithms are not easy to learn. It's hard, just see and do more. If time is limited, then just brush the real questions and brush them several times. If you have enough time, then after finishing the real questions, you also roughly know the algorithms that are often tested in the Blue Bridge Cup and your weak algorithms. At this time, you can go to other oj to practice topics.
3. Students participating for the second time:
First of all, don't think that it is the second time to participate in the college, it is really easy to waterloo, and it is still necessary to prepare well. You can review the real questions first. If the provincial competition questions cannot satisfy you, you can also go to the national competition real questions, or go to other oj to brush the questions. Since this is the second time to participate, you can properly let yourself learn more advanced algorithms. Of course, the basic algorithms should also be consolidated. Don't forget this~
4. Students participating for the third time:
You are participating for the third time. You are a mature player. Do you want my advice? Just kidding~ Generally, the students who participate for the third time are juniors. At this time, they may be busy with things such as postgraduate entrance examinations and job hunting, so the preparation time may not be so abundant, but the first two years of writing questions I should have accumulated a lot of experience, but even if I don’t have much time, I occasionally take a little time to do questions, such as doing one or two questions a day. Status and feel are really important!
【Exam Skills】
1. Students who don’t usually use DEV should be familiar with DEV before the exam, such as how to create files/projects, how to single-step debugging, etc.
2. Remember the bunch of header files that may be used. Of course, the universal header file (#include<bits/stdc++.h>) can also be used.
3. Use functions as much as possible where functions can be used, such as sort, next_permutation, etc., to save time and effort, and STL is the same.
4. Some problems are easier to use in other programming languages, such as Excel (date problem), Java (large number problem), etc.
5. When analyzing the topic, you can scribble and write more on the scratch paper, so that the ideas are easy to come up with, and don't forget to bring a pen.
6. It is recommended to drink less water and bring some food appropriately.
7. Fill in the results: most of them can be violent, or you can use other tools to get the answer (as long as it does not violate the regulations), remember to be careful, you can change the method to verify the results if you have time, but don’t stay for too long on a question, Otherwise, it will affect the following program problems.
8. Fill in the blanks with codes: generally recursion, finding rules, etc., if you really can’t think of it, you can try it casually, it’s easy to try it right.
9. Program questions:
① The program questions are scored according to the proportion of the tested samples. If you really can't think of a perfect AC solution, you can also mix some of the scores first. Here are some specific examples. The 10th question of the ninth group B has the largest product. If you don’t have a good idea at first glance, and then you usually don’t have much time to complete the last question, in order to score points, you might as well think simple. This question is nothing more than giving you a bunch of numbers, what can the numbers have, plus or minus zero. Directly consider the case of all positives or all negatives. The code for these two simple cases is not complicated to write, right? It is impossible for all the test cases in the background to be complex. Generally, there are gradients in the test cases, from simple to difficult, from common to extreme cases, so even if you only write for simple cases, you can take partial score. Another example is the risk measurement in question 7 of the mock competition. When I saw it, I thought, "It's over, I haven't learned it yet and checked it out." What should I do? Pay attention to the title, there is a sentence called "if the two points of the query are not connected, output -1", the implied meaning of this sentence is that at least one set of test samples in the background is disconnected. Instead of leaving it blank, you might as well write a program to output -1. If there are 5 sets of test samples in the background, you will also get 1/5 of the score.
② The Blue Bridge competition system can't see the result after you submit the code, it just won't tell you whether it is WA or whether there is a timeout. Usually there are only one or two sets of test samples provided by the topic. In order to further verify the correctness of your code, you can find a few more sets of test samples to test.
PS Some students want to know when the results of the provincial competition will be released. I have the impression that the results are very fast, two or three weeks after the test.