Whenever I learn a new algorithm or data structure, I always spend a lot of time finding problems related to that specific topic from previous contests on Codeforces or some good Competitive Programming Website. Many people told me to use Codeforces tags. Still, I feel that they are too many problems that will blow up your mind, or you might end up solving a similar type of problem-based on a topic(algorithm or data structure) which means you are not learning anything new and is counterproductive.

After a year of extensive search, I have found out 5 good resources which solve this problem.