Most leetcode problems I have seen are not research problem statements and usually require applying one or two algorithms taught in any CS program. So I have to

Most leetcode problems I have seen are not research problem statements and usually require applying one or two algorithms taught in any CS program. So I have to disagree. EDIT: Obviously even some of the most elementary Algo 101 problems were research questions at some point, and led to published papers, but that's the reason people write textbooks and use them in college, so newcomers don't have to redo the foundational work.