Quiz4J

Google Code Jam is a coding competition in which professional and student programmers are asked to solve complex algorithmic challenges in a limited amount of time. The contest is all-inclusive: Google Code Jam lets you program in the coding language and development environment of your choice.

The competition is held sometime in Augusts to October, though practice problems are available throughout the year and you can solve the problems asked in previous years. The implementation and problem quality is very good as you can expect from Google. All in all - a must look page for a puzzle lover.

The site run one or two contests per year. Each contest asks that you come up with your best solutions to a set of related computationally intensive problems.

Its pretty addictive and its fun to work out a solution to the problem and optimize it to improve your standing. The problem are pretty good and getting a solution to a problem should be easy! To improve your ranking though you have to find better algorithms and reaching the top is pretty hard!

TopCoder's global community of developers competes here in skill-based challenges representing every stage of the software development process. TopCoder is competition clubbed with a development site - that is, real projects are handed out as competition and the best code is used by the client in real software. The winner usually ends up getting a cash prize.

CodeChef is India's first, non-commercial, multi-platform online coding competition, featuring monthly contests in more than 35 different programming languages. Winners of each contest get sweet prizes, recognition from their peers and an invitation to compete at the CodeChef Cup, a live event held yearly!

The programs are pretty tough and someone who's looking for some challenging and brain racking questions should give CodeChef a visit!

No programming puzzle list could be complete without a mention to project Euler which is a series of challenging mathematical/computer programming problems that will require more than just mathematical insights to solve. Although mathematics will help you arrive at elegant and efficient methods, the use of a computer and programming skills will be required to solve most problems.

Project Euler is the touch stone for many who wish to test their programming skills! With about 250 puzzles it is one biggest programming puzzle site available.

This is a blog of programming puzzles written by Dave Thomas, who’s most famous for the groundbreaking book, Pragmatic Programmer. The 21 Kata's revolve around puzzles relevant to real world programming - so this is a good place to brush up on your coding skills.

The Kata's are pretty well written - in fact some of them are not so much about coding but rather developing good coding habbits. Code Kata is definately worth a read even if you dont end up solving any of the Kata's!

The types of contest on this site are pretty similar to those on Al Zimmermann's Programming Contests. Basically each contest asks that you come up with your best solutions to a set of related computationally intensive problems.

I found the contest a little harder to understand than Al's but they should be as much fun. Getting a solution is the easy part the tough part would be reaching the top!

FaceBook has had a long standing programming career competition where it proposes to hire the best among those who attempt the competition.

The problems are classified as per the difficulty and to send a solution you need to solve a puzzle (involving operators and number conversion) to figure out where to email the solution. Pretty much the setting needed for a puzzle solver!

UVA Online has the most comprehensive collections of puzzles that would cover more or less most of the type of programming variations that you could face.

The site is easy to navigate and considering the number of puzzle - a site definitely worth looking at.

Along with UVA Online this is one of the more traditional puzzle sites available. With more than 1400 problems its one site worth looking at.

JROBOTS (jay-robots) is a clone of an old game called CROBOTS. Some bots fight in an arena, firing missiles and avoiding enemies projectiles. At the end only one will survive! This game is involving, but it is not interactive: you must develop the AI algorithms of your own bot using the Java language, then you upload it in the arena and follow online its fights against other bots.

The concept is pretty interesting and might be fun to build your own bot!

The contest in very similar to JRobots but the web site is much well designed and easy to use. The navigation and tutorials pages are pretty neat and it should be pretty easy to start designing you bot with a well chalked out API.

I would perfer this site over JRobots for its cleaner web design, clear documentation and help wiki.

This site allows you to create your own puzzles (programming puzzles, Mathematical riddles and Logical riddles) with more type of puzzles to be supported soon. I have used scarky for some of the Programming Puzzles on this site - you can have a look at them on the home page! You can also see recent puzzle that people have created using Scarky here.

Finding good puzzle would take a good digging around but if your looking to host some of your own programming challenges then Scarky is a pretty good place to begin!

Quine is a program that generates a copy of its own source text as its complete output. Writing a Quine is challenging stuff - give it shot and try writing one!

This site does not run a competition but has a huge compilation of Quine in various programming languages. The author has a submission page but I can't say how active it is (considering that I never wrote a Quine myself)!

Mindcipher while not a programming puzzle site - has to be the biggest puzzle site out there. It has various categories of puzzles - Mathematics, Lateral Thinking and Traditonal puzzles. The site is well designed with the questions and answers(hidden) and comments(spoliers usually marked and hidden).

There is a huge active community following and you could be lost in it for hours solving the myraid of puzzles that they have! If your looking for break - then this is the site to visit.

Here are list to other places that index programming completions.

1. http://www.algorithmist.com/index.php/Programming_Contest_Calendar - This page covers up coming programming competitions, mainly those that a based on algorithms (greedy algorithm, backtracking, travelling salesman). Some of the competitions mentioned would already be covered in my list above.