Search 100+ Online Judges (ex: Reverse a Linked List, FizzBuzz, Maximum Subarray, etc.)
1. GeeksforGeeks Practice
12. Project Euler
20. UVA Online Judge
27. CodeAbbey28. CodeStepByStep
29. Elements of Programming Interviews Judge
30. CodeKata31. CrowdANALYTIX
33. TunedIT34. FightCode
35. HPC University35. MLComp
- Google Code Jam
- Facebook Hacker Cup
- Most are based on the Online Judge system
- TopCoder, CrowdANALYTIX, Kaggle, ChallengePost and TunedIT have their focus on Data Science/Projects
- Codingame and FightCode have their focus on game playing programs, so this includes intelligent solutions, Machine Learning, AI
- MLComp is focused on Machine Learning
- Rosalind is focused on Bioinformatics
- SQL-EX.RU is the only one in the list focusing on SQL. HackerRank added SQL, too.
- HPC University is focused on High Performance Computing (HPC)
- CheckiO is focused on Python
- Most on the list, especially the commercial ones are pitching employment, just keep this in mind
- HackerEarth, CodeEval, Talentbuddy, Codility, and Kattis are focused on Employment, have about 400 (practice), 185, 120, 90, and 600 problems respectively
- GeeksforGeeks Practice, LeetCode and LintCode are focused on Tech Interview Problems, (have about ?, 180 and 160 problems, respectively). LeetCode also has some SQL problems.
- HackerRank includes other specialties from the other sites like AI (Codingame), Data Science (TopCoder, Kaggle), Python Tutorials (CheckiO), Eulerian Problems (Project Euler).
- HackerRank provides a good calendar that contains events from other sites like HackerEarth, CodeChef, URI Online Judge, TopCoder, CodeForces
- HackerRank-only features: Functional Programming specialization, Bash specialization, Linux Text utilities specialization
- Brilliant.org is more on High School Mathematics, and also are not a competition site, but they have problems in Computer Science, too.
- PythonChallenge is a programming riddles site and is actually not limited to Python
Looking for Academic Online Judges?