Best courses to learn Data Structures and Algorithms in C/C++/JS, Pointers in C&

competitive programming? Best courses to learn Data Structures and Algorithms in C/C++/JS, pointers and competitive programming? Do you know any such good resources? I want to improve my problem solving skills. I also want to practice competitive programming, so any good courses for that? I want to practice pointers any good courses for that? I've free subscription to oreilly via my company.