6 tempting “Coding challenge sites” for Dev to compete

1.Codeforces

Codeforces is a platform where programmers can participate in competitive programming competitions. Here, each round has a time limit and how to divide points among the participants.

This coding challenge site has been introduced since 2009, and is run by a team from ITMO University led by Mikhail Mirzayanov. By 2018, more than 600,000 users had registered to participate in the challenge here.

Considered as an interesting programming and algorithm practice site, Codeforces is divided into 3 Div:

• Div 3 is for people with rating <1600, with requirements to join.
• Div 2 is for people with rating <1900, without requirements to join.
• Div 1 is for people with rating> = 1900,  without requirements to join.

Div 3 and Div 2 are challenging equivalently and not of too great difficulty. However, in order to enter Div 3, you need to meet some more specific requirements from the administrator to filter your eligibility to participate. Meanwhile, programmers consider Div 1 quite difficult with challenges requiring a relatively deep dive-in. 

Regarding outstanding points, CodeForces is a great platform for those looking for fun challenges to build up skills and join teams that match their needs. The Gym feature is also very unique, where programmers can practice their skills in specific challenges and see their rank at the end of the challenge.

2.CodeChef

Started as an educational initiative by Directi - an Indian software company in 2009, CodeChef is a competitive programming community of programmers from around the world, promoting study culture within the IT community.

Depending on your level, you can choose from a range of pre-classified challenges on the website. In addition, the highlight feature of CodeChef is that users can communicate with other programmers to ask questions they are wondering, or to answer problems raised by others.

Some of the main functions:

• Practice
• Compete
• Discuss
• Competition
• Campus chapter

With its high socialization, Codechef is honored as one of the largest competitive programming platforms. CodeChef opens the platform for anyone to run programming competitions with a tool called campus chapter.

The platform also hosts three award-winning contests per month to encourage coder communities called Long Challenge, Cook-off and Lunchtime. The Long Challenge lasts for about 10 days, the remaining 2 competitions take place in a shorter time. Programmers can write code in the online editor CodeChef IDE and choose from one out of 35 available programming languages.

Cash prizes for these coding contests are around 700 USD and may also include other free software.

3. CodeWars

As its name would suggest, Codewars is a world where programmers participate in a series of competitions, challenges to "climb rank". Rank will be calculated based on the point called kyu and this score will be high or low depending on the difficulty of the problem you solve. After figuring out the algorithm for a particular challenge, you can view other people's answers to compare how your code is written and how effective your code is.

Main functions:

• Kata (programming practice)
• Kumite (challenge 1-1)
• Forum
• Wiki

Codewar impresses the community by its eye-catching interface with distinctive ways to present challenges named katas, where programmers gain other skills and challenges in kumite. Rather than just learning to code, this platform offers an interesting experience on challenges to the user. You can tackle these challenges online in the Codewars editor in over 20 available languages. You can also view discussions for each challenge as well as other participants’ solutions.

4.Hackerrank

HackerRank website is a popular website for those who want to improve their coding skills, with over 7 million participants. Not only is it a place for good programmers to compete in world-class challenges, this is also where newbies can practice and improve their skills. In addition, HackerRank also offers opportunities to find suitable jobs through recruitment competitions organized by the Company, mainly focusing on algorithms, AI, database, math,...

This is a practical recruiting platform that evaluates a programmer's skills in more than 2,000 companies around the world. The web's features allow tech employers to objectively judge developers through challengestesting real professional skills .

Main functions:

• Practice coding
• Prepare for the interview

Specifically, to have the opportunity to receive bonuses directly from sponsorships of big technology companies, please follow and participate in Hackathon events run by HackerRank.

5. LeetCode

If you are looking for a good foundation to help improve your skills, broaden your knowledge and prepare for technical interviews, then Leetcode is your answer. With the goal of being fully prepared for programming interviews, you can choose problems to solve from categories such as: System design, algorithm and database, and enter competitions. or fake interviews.

Leetcode is used by hundreds of thousands of developers with a collection of algorithms from Amazon, Facebook, Google, Linkedin, etc. v. In addition to more than 1,400 practice questions, the challenges on Leetcode are clearly divided into 3 different levels of difficulty.

This site has a plus point, which is measuring your performance / runtime code, and then comparing with others, assessing whether your code is optimized or not, to which direction you should follow to improve efficiency.

On the programmer's forums, the site is rated as follows: “LeetCode has a very large collection of the latest algorithmic challenges out there. Their topics require knowledge of data structures like binary trees, heaps, linked lists ... so their problems are often more difficult than the general, yet very interesting and interesting. Besides, they also have a Mock Interview program that simulates monthly job interviews or code competitions.”

6. Viblo Code

Many Sun*'s passionate products developed by R&D Unit is a place that allows programmers to practice their coding skills, as well as thinking about their algorithms. Through the Challenge of Viblo Code, you will have more opportunities to practice how to use, as well as optimize algorithms with your favorite programming language. Here is a system of exercises, when successfully solving these problems the user will receive a corresponding score and form a ranking to evaluate rank.

In addition, Viblo Code also has a function "Contest" - facilitate creating online contests. This feature has been used by the HR department in Da Nang to successfully implement the Code Challenge program in April 2019.

In Vietnam, the model of Viblo Code is actually not too new since some similar sites have even been developed for quite a long time. However, not all platforms support the contest operation. Moreover, the system has many scoring modes for different types of contest, which can be considered as an outstanding advantage when it comes to Sun* products. 

Viblo Code is aimed at the main target - students. While not all of them are good at English, bilingual development in both English and Vietnamese is also an attractive and highly-appreciated factor of this product.

In the coming time, Viblo Code is expected to have many feature updates, aiming to promote interaction among users, build a stronger community, through the addition of functions related to contributing articles, sharing answers, Contributions Ranking,...

The above are 6 "arenas" of code receiving the attention of numerous programmers. There are also many other interesting platforms, so please comment and discuss together to find out other useful coding challenge sites!

Content Advisor - Trần Đức Thắng (Group Leader - R&D Unit)