Well-known OJs include: rqnoj, Urals, spoj, vijos, usaco, sgu, pku (POJ), zju (Toj), tju, UVA, etc.
Famous OJ website:
China OJ:
On-line evaluation system RQNOJ:/
Vijos: An Effective Informatics Evaluation System: (resumed on July 12, 2008)
English OJ:
Peking university pku: /OnlineJudge/ (mostly in English)
USACO: (most English)
Zhejiang University OJ:/ (English)
First of all, OJ, a well-known brand in China:
Peking University /POJ (Peking University judges are ACM/ICPC online)
Address:
/JudgeOnline
Introduction:
The question bank of Peking University, which I mainly do, has a large number of questions and the functions of OJ are perfect. Moreover, it also provides free OJ system download, so you can use the provided system to build your own OJ. There are many problems, thousands of them, but there are also many water problems. In this regard, because of the large number of questions, there are naturally many water questions, but this does not mean that the quality of Peking University's questions is not high. There are still many problems in Peking University, which have been solved.
Recommendation degree (maximum 10):
eight
Recommended practice:
If you are a beginner or just want to improve the accuracy, then do it according to the AC rate to ensure the 1Y rate; If you have a certain OIer level, you can complete 40~50 questions per page; If it is Daniel, then try to do it; If you want to train a specific project, you can search pku topic classification online. Personally, I think there are more dp problems and math problems in Peking University.
ZJU/ZOJ (Zhejiang University Online Judge)
Address:
/
Introduction:
The question bank of Zhejiang University is one of the earliest OJs in China. The number of questions is also close to 2000. I don't have many questions about zju, so it's hard to say the quality of the questions. OJ system is not as friendly as Peking University, but its function is not bad. It should be a substitute for Peking University.
Recommendation degree:
seven
Recommended practice:
None (refer to the practice of Peking University)
HOJ
Address:
/(Netcom agent)
Introduction:
Harbin Institute of Technology (OJ) started relatively neither too early nor too late. There used to be a lot of big cows. Now the number of topics is close to 3000, and the difficulty is uneven. Because the school began to pay attention to its ACM, there have been frequent activities recently. But the friendliness is poor, the system construction is not perfect, but the function is not bad.
Recommendation degree:
six
Recommended practice:
not have
Then there are some lesser-known or relatively new ones:
RQNOJ (online judge of Renqing.com, OI problem evaluation system of Renqing online informatics)
Address:
/
Introduction:
RQNOJ gradually matured after one year, and the number of topics and users also increased a lot. It is very commendable for some new functions recently launched by RQNOJ. There are often some competitions to participate in.
Recommendation degree:
seven
Recommended practice:
Do some difficult problems
On-line system for speed informatics judges
Address:
/
Introduction:
Now when it comes to OJ, I have to mention that Vijos. Vijos is a referee system made by Vivian Si Nuo (that is, Liu Kang of the High School Attached to Hunan Normal University, whose personal homepage is/,and now it seems that she can't get on =). =). It used to be an innovation competition, but now it is very popular. But Vijos has a lot of things, and the server is unstable and slow, not to mention it is turned off from time to time. Vichos's Past, Present and Future > (/toj
Introduction:
Maybe everyone thinks it's Tongji's question bank. Actually, this one belongs to Tianjin University. Because the author is from Tianjin, he has a unique feeling for this OJ ... Although he hasn't done much, he is slightly worse than zoj on the whole, and the quality of the questions is uncertain (I said he hasn't done much ...), so I usually use it for competitions.
Recommendation degree:
five
Recommended practice:
No, you can compete. Note that this is an online competition, not a virtual competition. Virtual ... just open it and you will know. It uses TOJ's own question bank to generate competitions ... In fact, this design is very novel, so you can test it. Suitable for testing in a team. ...
NKOJ (Nankai Online Judge)
Address:
/
Introduction:
This is OJ from Tianjin Nankai University. Most people don't know, do they? Before reading the following introduction, you can go up and have a look and experience. You will find that you will feel very comfortable through the application of Ajax technology and fresh interface. And NOJ seems to have another function that does not appear in the rankings and status, which is very intimate. Topics are NOJ's biggest weakness, and there are not many. The quality is average. However, because Chinese and English questions are mixed, there are more Chinese questions (compared with Peking University), and people who want to do Chinese questions can also come here to have a look. In fact, nkoj is more beautiful, faster and more stable than vijos ... it should be much better than Vijos.
Recommendation degree:
five
Recommended practice:
Do Chinese questions.
Next, let's talk about OJ abroad:
SGU (online debater of Saratov State University)
Address:
/usaco% 20training/