Tutorialspoint is one of the best websites available for online education. When I took admission in B.tech I did’nt have a habit of jotting down the notes and this website helped me to be updated with all the content. I’ve excelled data structures basics through this website. The content available is genuine and in very simple language which is easy to understand. It has most of the subjects notes available. And the best thing is you can even download the pdf of the subjects theory chapterwise or whole.