Competitive Coding💻 is not just a subject it's a sport which you can't master only with theory, it requires a lot of problem solving practice.
Many people think that it's only for people with high IQ😵 , But trust me it is not the case😄 . Anyone can do well with competitive coding provided his/her concepts on data structures and algorithms are strong.
MyCodeSchool is a really great channel for understanding theory of programming, It covers various concepts on DSA and time complexity.
Clever Programmer is suggested if you are a developer and would like to same some project in React or Python.
Hackerrank Is the place to start after learning your first programming language.It consists of basic problems which help to make strong fundamentals.
CodeChef youtube channel is just amazing it has some great content with volunteers giving sessions on various concepts.There are 3 fixed contests on platform Long challenge, Lunchtime and cook-off highly recommended to participate in them every month.
Some Great theory out there on hackerearth these notes could be used as a reference for beginners or for revision at later stages.
Should participate in Codeforces contests and try to improve ratings.Practice problems are quite good on this platform and should be practiced in order from low difficulty to higher difficulty.
Great theory on GFG it has notes,examples and practice problems on everything out there.Beginners can highly depend on this site and channel and improve themselves or use this site whenever they get stuck on some contest problem.
https://www.geeksforgeeks.org/
One of the best books For clearing programming interviews, Suggested at little later stages when you get your hands good at problem solving and interviews are approaching.
There are normally Two approaches out there !
1)Practice and Learn
2)Learn and Practice
Happy Programming!🎉🎉🎉