Nice ACM-ICPC article

Article: http://258go.5d6d.com/thread-13-1-1.html

 

First recognized by ACM
I first heard that the ACM/ICPC competition was mentioned by Teacher Zhang in the algorithm class on the 3rd. At that time, our school was just getting started to participate in this activity, and I didn't care too much, I always thought it was a very distant thing. In fact, at that time, I was never quite able to achieve our current achievements. I really entered the magical world of ACM/ICPC. I had to mention xmutank, the contestant of our school in 2004. I was very interested in this competition only after listening to the wonderful speech of pipo Senior brother, start a challenging ACM journey. First, the real training started from the winter vacation of 2004. Maybe it cannot be said that training should be called "playing". In fact, I have always liked to call it "playing ACM ", I think ACM/ICPC is a game that anyone who loves challenges and computers will like. In the face of the challenge of one-way problems, use the most elegant and concise algorithms to solve the problem in the shortest time. It's not a joke to be so excited that you can't sleep all night. The beauty of algorithms, the beauty of code is no less than the beauty of games. "Playing ACM" is as addictive as playing games. I don't know if other acmers have such feelings. At least I was so excited. At that time, my "playmates" were ferret_chao (Zheng Chen Chao, CSD 02, my teammates in 05 years) and arxor (Zhang Chi, CSD 03, my teammates in 06 years ). Our main activity area is PKU online judge, which is the famous poj. At that time, the scale of poj was far inferior to the present, and the total number of questions was about 1200. I still remember that the top one was daofeng of Peking University, and the number of questions was only 600, the three of us later surpassed the first in that year. At this time, everyone is very weak, and the problem is basically not done. All the questions are those with the largest number of questions. The three of us are not familiar with each other. At that time, xmu was not mixed in poj, and only three of us were active, the result is that everyone is holding on to it, and no one wants to be exceeded. One of them has a question, and the other two are immediately following up, so they have to pass it over. Once someone else makes a question, he will surely be proud of it for a long time. The joy of competition remains vivid in retrospect for many years.

Summer fighting
If the winter vacation in is a kind of enlightenment, the summer training in can be called a real hard training. We can say that a few of us have come by ourselves. In fact, many of our other ACM strong schools are completely different. We have never had formal training from start to end and rely entirely on the information collected everywhere, this is related to the fact that our school had no experience in ACM. I have learned a lot about this. As far as I know, I have introduced ACM questions as an experiment in the algorithm class offered by Mr Zhang defu. In addition, our ACM teams have also left a lot of information collected previously. In any case, we did not have any experience at the time, so we started our training with an introduction to algorithms. In, our school had two teams: I, ferret_chao and jason_chen (Chen jingchi, CSD 02), and arxor and xmutank (Wei Lijun, CSD 01, 04 years old players) and Lucifer (Dong Xu, bio level 03, once participated in Noi ). At this time, we began to solve some difficult problems. Instead of fighting alone, we made full use of the collective wisdom. In addition to hard thinking, the three players will also exchange ideas and ideas for solving problems. At that time, the three members of our team lived together and went in and out every day. From getting up at A.M. To a.m., almost all except for meals, they were doing questions, thinking, and discussing, it is a kind of joy. Of course, after is the entertainment time, no one can take a whole day to get tight, and work-and-rest combination is king. That is, this investment and communication have greatly increased our knowledge accumulation speed and Capability Improvement speed. This time is the fastest time for us to increase our strength, and there are new gains almost every day, learn new theories or solve new classical questions. I firmly believe that practice is the best way to learn. I always think that self-learning is the most important quality for all acmers and even all computer scholars. As mentioned above, the competition in the Chinese Division must pass the online preliminaries, and each school can only have one team to enter the on-site competition (the schools that have participated in the world finals can join one more team, the top 10 schools in the preliminaries can also join one team. We didn't think we could enter the top 10, so we can only have one.) But we have two teams. Therefore, to participate in the on-site competition, our team must first defeat another team. Therefore, in addition to training, we focus on the situation of another team. Every warm-up match beat them with full strength. To be honest, their foundations are better than ours. One is an old player of years and the other is a noi veteran. However, although we have a poor foundation, we are very competitive. You must know that all three of us are giving up the opportunity to take the Postgraduate Entrance Exam and devote all our energy to this competition, why didn't I want to pay so much that I couldn't even qualify for the pre-finals? (at that time, I promised that I would be able to win the silver medal in the pre-finals, but I didn't realize it later. I only provided the opportunity to review the pre-finals ), perhaps it is this sort of pressure that allows us to surpass ourselves once and finally defeat them three times. In, there were three divisions in China: Chengdu, Beijing, and Hangzhou. Both of our teams were out of line in the three preliminaries, and our team beat each other with a slight advantage, in addition, the Chengdu division played an outstanding role in obtaining two outgoing permissions, so we finally went to Chengdu and Hangzhou, where they went to Chengdu and Beijing.

Chengdu and Hangzhou
The trip to Chengdu was the first time I took a plane, the first time I took a train, the first time I went out of the province, and the first time I took part in a national competition. The first time I got the silver medal, I had gathered too many times. The first time I stepped onto the game, I was absolutely deceiving myself when I was not nervous. I don't know what happened to others. Chen and I were sleeping almost one night and filled my head with tension and excitement. To be honest, the competition in Chengdu was not very good, and Sichuan University did not seem to have any experience in organizing the competition. The question was too difficult and there was no simple question trainer, faced with a bunch of difficulties, there is a feeling of being attacked. At that time, the first question was an extremely complex and disgusting simulation question. The reason why I chose this question was that I had no idea about other questions, I am confident that only these questions depend on carefulness and programming skills. After determining the question, I began to think about the code. Chen Chao and Jing Chi considered other questions. It took me more than an hour to complete the code, and I had to submit it for the first time. As a matter of fact, I was surprised to pass this question smoothly. At that time, no one on the court had solved this question, after the game, we knew that the entire game was over and only two teams had passed that question. At that time, I was definitely an explosion of character. This explosion gave me great confidence in the simulation of questions. I was dubbed "The King of simulation questions" by my teammates. Based on my extraordinary performance, we regained our confidence. After some painstaking meditation, we solved a problem and finally got a silver medal as 16th people. This silver medal is the first silver medal that our school has obtained on ACM. It is also an affirmation of our hard training efforts over the past few months. The trip to Hangzhou two weeks later was a teaching evaluation. No one was paying attention to us. This time we went on our own journey. After the baptism of the trip to Chengdu, the tension has subsided, and the rest is the passion and confidence to face new challenges. Here, we met the famous loutiancheng building instructor. However, it seems that the teacher is not in a very good status, and the performance is not as good as ours. This also satisfies our vanity. This time, one of the three members made a question, and finally won our second silver medal with the ninth name of the three questions, ending the 05-year ACM journey.

Beijing, Shanghai
One year later, half of the old team members retired, and three new team members joined (Zhang junbin CSD 03, Xiang guangte CSD 05, Wu duimin software 05). At the same time, due to our breakthrough in the medal of the previous year, ACM/ICPC has gained a lot of popularity in our school. In addition to us, some enthusiasts are doing question training. Now poj can search xmu to see a lot, it is not as simple as we were at the beginning. We hope that as the school attaches more and more importance to the ACM competition, more and more students will participate in the competition. They are precious reserve forces and they will have the future of our ACM competition. In fact, in addition to being honored and affirmed, we are more pleased to make our efforts to attract more students to the competition and enjoy the game. Objectively speaking, our school has a relatively small investment in ACM. We do not mention the exaggerated investment of nearly one million RMB in Shanghai Jiao Tong University, that is, it is quite inferior to other schools, there is still a huge shortage in terms of Pre-competition training, training equipment rooms, and competition funding. However, it has been greatly improved. This is also one of the results that our strength has been affirmed by the school. Last year, we also set up a female team (LU Wuling CSD 02, Lin QianYu CSD 05, and Huang Wenxiu CSD 05). Although the team is relatively weak, but it is indeed a history. This time, my teammates are Zhang Chi and Xiang guangte (CSD 05 ). Objectively speaking, this team is the most powerful team in the history of our school. I am good at coding and have a strong practical ability. I have a solid theoretical foundation and a profound grasp of the mathematical skill, there is also a long-tested item in Noi. We are confident that we have the ability to challenge any strong team in China. During the summer training, we were confident that we went to the gold medal this year. In poj's warm-up match, I won the first place twice, which even increased my confidence. The trip to Beijing started in this context. Before I went there, I was full of hope for Tsinghua. Like most people, I once dreamed of achieving Tsinghua. But the truth is cruel. I once again realized that Xiamen University's reputation is not without reason. Coupled with the gloomy weather in Beijing, the organization of the Tsinghua competition was ineffective, and the image of Tsinghua was almost wiped out. In the following field competition, we first had a simple question by cent, then I had a search, and finally he had another game. Although we only had three questions, but because we had a short time to do the questions and had very few penalties, we finally got the second place after the four questions of the University of Science and Technology of China, we won the first gold medal and the World Championship. There are many reasons for this achievement. The first is the competition held by Tsinghua. They cannot assign teams to participate in the competition. As a result, the building instructors who are famous for the earthquake did not take the lead, second, Shanghai Jiao Tong University, a traditional strong school, has no teams to participate in the competition, which virtually reduces potential competitors. Of course, the most important thing is that we already have enough strength to challenge the gold medal. The Battle of Beijing is our battle of fame. The ACM community is like a battle of rivers and lakes. Here, your greatest battle is your strength. When we enter Shanghai University to participate in the competition, we will no longer be unknown. If we are not careful, we will be treated as a cool man at Xiamen University, making us very vain. If the gold medal in Beijing depends on the brave performance of Xiang guangte, the gold medal in Shanghai is based on my character explosion. At the beginning, I had a simple question, after discussing with Zhang Chi, I went through a tree-like DP and then another search. Later, Xiang guangte had a math problem, and finally I had another search after constant optimization. In the end, we ranked seventh. We ranked first with two Tsinghua teams, two submitted teams, and two Fudan teams, since the submission and Fudan have won the first place in other divisions and are not counted in the ranking, while the same school only counts as one, we finally ranked second. It is a little pity to get the second one, but it has already exceeded the expected results. The task of winning the championship will be handed over to the future teachers and sisters.

Tokyo
Only when I go out can I know the world is big. It's a bit cool to stay in Xiamen all day. To be honest, I have a bad impression on the Japanese nation. I have heard a lot of negative reports in China, and I always think the Japanese are very cool. The actual situation is completely different. We don't have time to go to the Tokyo City, but the flight from the airport to the Hilton Hotel on the Tokyo Bay gave me a very beautiful and clean city. The Japanese are indeed quite humble. They feel very profound when buying things in various stores, and have a surprisingly good service attitude. Lenovo said that the behavior of some domestic merchants is indeed amazing. However, this may also be because we live in the Tokyo Bay Resort, which is a high-consumption location even in Tokyo. This ACM/ICPC world final was jointly organized by the IBM Japan Branch and ACM Japan Branch. The competition venue and the Competition Venue are different from the domestic arena, from the Disney half-day tour before the competition to the technical lectures provided by IBM, from the opening and closing of the wonderful party, thoughtful and considerate settings at the competition venue and cybercafe every night all reflect their attention to the competition. The organizers have repeatedly stressed that this is not only a competition, but also a world-wide event to provide a communication platform for future elites in the computer industry around the world. However, it is a pity that we have to let them down. Why do we say so? It is very simple. The English skills are insufficient and there is no way to communicate. Without going out, I really cannot understand the significance of English as a world language. No matter which country or mother tongue speaks, as long as I can speak English, as soon as we went out, we became half a deaf-mute guy who had to look at the envy and secretly decided to go back to learn English well. Finally, let's talk about final's feelings. I 'd like to say that this competition is the worst we 've ever experienced and the most vulnerable. In this case, it seems a bit suspicious. At the beginning, we performed well. I had a simple question, and then we had a simple question. The competition lasted for about an hour. At this time, he made a mistake. He started to do a math question about air pressure. This question is his strength, it is a pity that this is the second difficult topic in the entire game. In the end, only two teams have crossed the competition (the first in Warsaw and the second in Tsinghua ), as a result, he spent all his time on the top and never solved the problem. This is equivalent to losing a general employee to our team. Then Zhang Chi made a mistake. He picked a graph theory question, which is also his strength. The result was the most difficult one, and there was a wrong question. No one had ever done it in the end. I chose a simulated question with moderate difficulty. Originally, this was my strong point, but I don't know which guy made the question and the question was so obscure that I read the wrong question three times in a row, it took a long time to solve the problem. After the third question is completed, it takes three hours. At this time, Zhang Chi also gave up the most difficult question. There are three questions that can be done in front of us. One is search and the other is plane ry. In fact, this is a recovery opportunity. A better choice is that I should search for the attack, and guangte and Zhang Chi have a geometric question, or three people work together to attack a question. This strategy can still be made up of one or two questions. However, it was impossible for me to draw out the question. I chose a ry for my mind and another ry for relaxation. The final result was that no one got it, and the number was 44th, which revealed that we used to work on a single task in normal times and the weak points of ineffective cooperation at key times. In my opinion, searching is my strong point in normal circumstances, and I have the ability to develop that question, at that time, I did not do this because I had been confused about the previous question. As a result, I had a sense of fear for that complicated question. As a result, I missed the opportunity and my psychological quality was not enough. In any case, I can go abroad, go to the world finals, and see a world that is totally different. I am satisfied to see a great cow drifting across the world, and it has made me gain a lifetime, a small loss is not a great pity.

Experience
The ACM Competition covers almost all aspects of computer science in the following aspects:
1. Programming Skills: proficient in a programming language: C/C ++, Pascal, and Java. Most OJ provides support for the above three languages, but final does not seem to provide Pascal. I recommend C/C ++ for the language, which is inexpensive. :)
2. Data Structure: Stack, queue, heap, binary count, query set, line segment tree ...... There are still some data structures that I have not mastered, such as suffix trees.
3. algorithms: search, dynamic planning, graph theory algorithms, recursion, recursion, binary, greedy, and governance ...... This includes the combination of all classic algorithms and classic algorithms, such as binary and greedy algorithms, search and graph theory.
4. Related Knowledge: Graph Theory, number theory, combined mathematics, computational ry, compilation principle, operating system, various mathematical conclusions ...... Sometimes you need to use some inexplicable mathematical conclusions. This kind of thing depends on the preferences of the topic. If you happen to know exactly what it is, it is your luck.

Training Methods
1. Question-making is king. If you have over 1000 questions, you are a good man. I think that reading, doing, and thinking are all about three questions.
2. Reading and reading papers, especially in terms of graph theory, number theory, and composite mathematics, many things cannot be learned in the classroom. Therefore, you must actively look for materials.
3. Read the problem-solving report. There are some difficult questions and there is no experience in similar questions. It is difficult to come up with a solution. In this case, reading some problem-solving reports will help you broaden your horizons and improve the ability to solve problems, however, it is absolutely impossible to rely too much on problem-solving reports. What you actually know is strength.

Team-Up Plan
1. The competition is a three-person competition. It is very important to cooperate with each other. It is best to have a plan for who is doing what and what others are doing.
2. Team formation should be reasonable: all abilities should be able to complement each other. For example, a team should have a strong math person and a strong code person. In short, the abilities of all team members should be combined to cover the scope of competition questions.

Competition experience
1. The psychological quality is good. The atmosphere is intense during the real competition, and the psychological quality affects the competition to a large extent. (In final, I was a little worse)
2. During the competition, you must pay attention to the selection of questions. It is too difficult to give up the questions. You should refer to the questions made by other teams on the field. It is generally easier to create many people, do not waste time on questions that no one is doing. (The lesson of blood must be learned)

Gains
I have gained too much. It can be said that participation in ACM/ICPC is the most cost-effective activity that I attended at the university stage. In addition to the most basic algorithms, there are a lot of classic algorithms in your mind. Other gains include:
1. Exercise mathematical thinking and improve the ability to solve problems
2. Programming capability and Psychological Quality
3. Analysis and hands-on capabilities
4. increase visibility
And most importantly, having fun with ACM is never comparable to any other boring course.

Postscript
The ACM world is full of passion and challenges. It is far from being described by a poor article. You can only learn the magic of experiencing it in person.