Summary of the 2015 provincial competition: the 2015 provincial Competition

Summary of the 2015 provincial competition: the 2015 provincial Competition

Reflection after "Jedi counterattack"

The first time I participated in the provincial competition, I felt very deeply!

There are 13 schools. Compared with other colleges, they should belong to many colleges,

Ps, simply regard the name of the formal team "Jedi counterattack" as the name of the team.

Let's start with the warm-up match, before the competition. I discussed the countermeasures. I was in charge of the main knock, and my teammates cb and ljf were responsible for reading the questions. After I posted the questions, I immediately found that question A was A question of expression evaluation and needed string processing, ljf seems to have said that he has done similar questions in oj before, so we will first let him write a rough idea on paper, and I will open the compiler and knock on the necessary header file, and some necessary templates. After a while, teammate cb immediately read question B and told me the meaning of the question. I found that it was about five minutes before the question was signed in, the test example has passed. Click submit, 1Y

Later, ljf said that I could answer question A, so ljf began to answer question A. cb and I helped my teammates check whether the code was correct on both sides. It took more than 20 minutes in the middle, after the call, I finally typed out the code, passed the sample and output data, and clicked submit, 1Y!

Afterwards, I tested various environments and various results in various positions. In the intermediate process, PC ^ 2 judgment systems were all kneeling. (it is estimated that the enthusiasm of the Q & A system was too high and I could not bear it for a while ~~)

In the end, both questions were 1Y. at, the warm-up session ended.

Am-Am

Formal competition: after getting the question, we still have some time to start the competition on time. Our team is not sitting like other teams, instead, the template that analyzes the algorithm question types frequently used in previous provincial competitions is quickly pushed to the compiler, this practice was learned from the teams around you during the competition held by Hangzhou University of Electronic Science and Technology. On the one hand, the main code operator can immediately enter the status and save time on the template,

When the competition officially started, we split the package and divided the questions into three parts: one from the past, the other from the middle, and the last from the back. After we found two English letters, immediately exchange questions to teammates with strong reading ability. This arrangement is to consider the overall reading level of the teammates. If the overall understanding level of the teammates is different, you can select one person to read the question, but you must read the question accurately and grasp the key of the question. Sometimes, as long as you read the data, you can grasp the ideas and practices of the entire question and start to read the question, cb found that question A was the strong version of yesterday's warm-up competition. After talking about the key to the question, ljf said that we only need to change the code of yesterday, we immediately found the print of question A yesterday, And ljf started to do question A. cb continued to read the question. I checked the code for my teammates and typed it for about 10 minutes. The test in this example was correct, after thinking for a while, I got a set of data and tested it. I found it wrong. So I checked it carefully from start to end. Finally, I found that something was wrong. I immediately corrected it, test data is correct. Click Submit and return Yes. The first 1Y is a bit excited. We have read the time. This time has passed for nearly 40 minutes. Let's take a look at the next question. At this time, cb understood question F and told us the question. It immediately felt like a sign-in question. When it was decisive, it quickly came out. After checking it again, it felt like there was no problem, I tested the sample once. Unexpectedly, what I imagined was a pass, and the sample was not passed !, I immediately calmed down and reviewed the question again. I checked the code carefully when I confirmed that the question was correct. I still did not find the error. At this time, I was speechless, I asked cb to help me check it out. cb immediately pointed out the error. It turned out that the location of the variable definition was wrong. (I couldn't see the error for a long time, and my teammates found it at first glance, this may be because your thinking has been confined to other aspects of the subject, but you have not paid attention to the real bug !) After the correction, check the other items and test several groups of data. If no problem exists, confirm the submission. If Yes is returned, the system breathed a sigh of relief.

At this time, it took about more than an hour. At this time, ljf understood another question and told us that the original question in the book was changed. We read the question again, I found that it was almost the same, so I knocked on the Code and handled spaces and other points of Attention Based on the question. I submitted 1Y and 3rd questions, and the pace started to steadily advance, I told my teammates the question I was reading at the beginning to maximize the average value. In fact, after reading the question, I felt that I needed to use a binary search. I asked two teammates and I had no idea, everyone was thinking about it. I suddenly got an idea. I felt like I was using a binary search. I went up and knocked on more than 20 rows and found that I forgot how to write it, later, I reflected that this was my mistake. I did not fully clarify my thoughts and wrote it. I did not recall the key point I forgot. I immediately thought of the template with it, I checked it and was disappointed that I didn't find the desired information. I was struggling. cb pushed it for a while and said that he had ideas. We asked him how to do it, he said they could use prefixes and operations. I immediately asked how to maximize the average value ?, He said that two Arrays can be opened, one for maintaining the prefix and the other for recording the prefix and the average value, and each time the maximum value is obtained, he asked for the ljf's opinion and felt that there was no problem, cb started to answer questions. During the process, we found that a good habit of cb was debugging. I wrote a few more printf and output the process results at any time, which is very helpful for code debugging, I saw a scene, so I checked the code. After a while, I knocked out the code, processed several boundaries, and tested the example! We did not submit it now. Instead, I thought about several groups of data, found that the test was correct, and carefully checked other places to ensure that nothing was lost. I clicked the submit button and returned 1Y. After this question was passed, we did not stop at all. At this time, ljf found that a question could be made using a network stream, so he tried it again. I and cb opened another question together, after reading this information, I felt like a bare minimum spanning tree (actually). Then I carefully read the meaning of the question and pushed the sample again. I found this was the case, one person told the remaining teammates about the question. I quickly went up and typed the template and found that the question was not as simple as I thought. I needed to use and check the set with permission to judge the question, it took nearly one hour to finish this question. However, it is because the knowledge points of related algorithms are too little and time is wasted. ljf is usually good at graph theory, I helped code again, but when the last sample passed, we did not hesitate to click submit, and the result still returned convincing Yes. Finally,

30 minutes before the end of the competition, we still did not give up, and opened another question. The last question was a problem of minimum transfer. After reading the question, the first thought could be the shortest path, at the beginning, ljf was able to construct a network stream. After hearing this, I felt that there was no need to use the network stream. In the last 20 minutes, ljf suddenly came up with another method. This time, we didn't ask specific ideas, let him knock on the question directly. In the last 20 minutes, the team next to him was unable to sit still. The team was prepared to leave the question, in the last 10 minutes, we passed the first group of samples, but we didn't have the second group. In the last 5 minutes, we still didn't have the second group of samples. We were still debugging the Code. At this time, there was no tension on everyone's face, because we were completely immersed in the problem-solving atmosphere and felt like we had reached a completely self-satisfied state. In the last few minutes, it's Time flies! The competition is over. five questions, all 1Y. I finally checked the rankings. It should be a silver medal.

[Reflection]

(1) The overall strength of Henan's colleges and universities has been greatly improved. Zheng Qing's strength is indeed strong. He won the championship and set an example for his study!

(2) The question of this competition is relatively watery, but it is a pity that it did not rush to the gold medal area,

(3) there are very few pure test algorithms, and the code capability is basically complete! There is still much room for improvement in exposing code capabilities!

(4) exercise too little at ordinary times, fast enough hands, relatively cautious, not decisive!

It's still too weak. The road is still long!