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projectEUREKA projectEUREKA Welcome to Project Eureka! Project Eureka is a collaboratively edited site for problem solvers/creators - regardless of problem or field. We are a bunch of math enthusiasts who decided to create a website for submitting and solving problems. However, project Eureka is not limited to math problems; any problem, puzzle, or trivia question can be submitted to project Eureka.
Based on the original perl golf, Code Golf allows you to show off your code-fu by trying to solve coding problems using the least number of keystrokes. You're not just limited to Perl either - PHP, Python and Ruby are all available too. Challenges are always open, and your entries are automatically scored so you can start playing right away!

Code Golf

Code Golf
USACO
+Ma's Reversing

Sphere Online Judge (SPOJ)

Sphere Online Judge (SPOJ) 2014-02-27 12:41:24 Codecha.org by Łukasz Kuszner Codecha (True Programmers' CAPTCHA) - the new project based on Sphere Engine - has just started. 2014-02-05 10:48:35 Badges for SPOJ by Ricardo Bittencourt (ricbit) by Łukasz Kuszner Ricardo Bittencourt (ricbit) made SpojTweet to track your progress on SPOJ, and give badges for your achievements. Please have a look at an example page from the site, an exemplary tweet sent by a site, Ricardo's SPOJ forum post and more SPOJ tools.
InterviewStreet InterviewStreet We built HackerRank to focus on you, the programmer. Here you will find a much larger set of challenges, including Artificial Intelligence and Machine Learning, in addition to classic ACM-style problems. We have also migrated the existing Interviewstreet challenges over to HackerRank.
What is Project Euler? Project Euler 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. The motivation for starting Project Euler, and its continuation, is to provide a platform for the inquiring mind to delve into unfamiliar areas and learn new concepts in a fun and recreational context. Who are the problems aimed at? The intended audience include students for whom the basic curriculum is not feeding their hunger to learn, adults whose background was not primarily mathematics but had an interest in things mathematical, and professionals who want to keep their problem solving and mathematics on the edge. Project Euler

Project Euler

There are many circumstances where we need to find out if something is a member of a set, and many algorithms for doing it. If the set is small, you can use bitmaps. When they get larger, hashes are a useful technique. But when the sets get big, we start bumping in to limitations. CodeKata

CodeKata