Contest websites

1. CodeChef - Regular contests including Starters for beginners, and many other formats.
2. Codeforces - Contests for each division are held regularly.
3. Atcoder - organises Atcoder Beginner Contests for beginners, which helps learn many new concepts. You can use This website to keep a track of the problems you solved on atcoder.

Youtube channels:

1. Colin Galen - Colin Galen is an International Master on codeforces and a youtuber. He has many streams of specific topics where he explains the topic and solves many problems. These can help you understand that topic better.

2. Utkarsh Gupta - Utkarsh Gupta AKA HealthyUG is one of India's best competitive programmers. He has videos on concepts like DP, trees and explains very well. He also takes special classes on Unacademy which are also great.

3. Luv - A great channel for basics and setting up environment. He has a nice CP/DSA Playlist.

4. Priyansh Agarwal - Uploads contest screencasts sharing his own though process. He also has a nice video on how to debug your code.

5. Code N Code - The main focus of this channel is to teach students data structures and algorithms and has many great playlists on Bit Manipulation, Number Theory etc.

Learning websites

1. CodeChef - Have their own CP and DSA Learning series, which has many relevant questions.

2. CSES - This website has many great problems, which will definitely teach you something.

3. CSES's CP Handbook and USACO's CP Book

4. Codeforces Blogs - We all agree there are MANY competitive programmers around the world, thus someone might have already written something about whatever you are trying to learn. There are many useful codeforces blogs that are helpful. So whenever you are learning something new and want to learn some tricks, just google <topic name> codeforces

• Examples of some useful blogs:
  • The Ultimate topic list
  • Graph problems
  • C++ tricks

5. CodeForces Edu Section - This provides insights on various topics like segment trees, binary search etc.

6. A2OJ Ladders - This has questions sorted based on specific ratings. This Channel provides tutorials to Ladder B problems.

7. CPP Reference - If you want to learn technical stuff about anything in C++, this website is best for you.

Practice websites

If you want to do problems about some specific topic, then i would recommend the following:

1. CP Algorithms - This is one of the most important places where you can learn almost anything related to CP. Everything here is nicely explained, and there are problems for each topic under their blog.

2. USACO - USACO guide provides important resources, extensive problems (from various Online Judges) along with progress tracking.

3. CSES - CSES problemset has some great problems.

4. Leetcode - Although this proves to be very important for interview preperation, leetcode is also home to some very challenging and great problems.

Tips

• Always sit with a pen and paper, and write/draw whatever that comes to your mind.

• For graph problems, you can use Graph editor for plotting the graph.

• For enhancing your problem solving speed during contests, you can use snippets. Code snippets are templates that make it easier to enter repeating code patterns, such as loops or conditional-statements. This Website can help you make snippets easily for VSCode/Sublime Text/Atom.

• You can join our Discord server and use TLE bot in it. Using TLE you can easily plot different graphs to understand your growth. The bot can also recommend you problems.

• Almost every error you get, is present on StackOverflow. So just google your error and you will most probably find it's solution on stackoverflow.