| CP-Algorithms |
E-Maxx Algorithms in English. |
| CodeForces Edu |
Lessons prepared by teachers of ITMO University. |
| CodeChef |
DSA Learning Series | CCDSAP Prepare | IOI Prepare | Programming Contest Syllabus |
| Topcoder Data Science Tutorials |
A list of tutorials written by respected Topcoder members. Many top programmers started learning data sciences from here. |
| PEGWiki |
A website with amazing in-depth wiki-like writeups on many topics. |
| Notes - HackerEarth |
A great crowdsourcing platform for tutorials. Also visit Code Monk. |
| CommonLounge |
Learn DSA | CP: From Beginner to Expert | IOI Training: Path to Gold |
| COPS IIT, BHU |
Great resource! |
| AlgoWiki |
A wiki dedicated to competitive programming, contains some standard techniques and related problems. |