What are some problem books in Single variable calculus?

Question

I have finished theory for single variable calculus taught at high school level, and want a book to practice problem solving in the same. The problem level should be difficult. Also mention some math competitions that include calculus in syllabus (at high school level).

EDIT 01 : The book should not be a tome of thousands of questions, a possible example can be "101 algebra problems by Titu Andresscu". The questions should be math contests style.

Thanks a lot.

Answer 1

I think M. Spivak's Calculus could be an excellent source to help settle your theoretical understanding of Calculus, and its set of problems is challenging.

Also, in a more conceptualistic point of view, A Course of Pure Mathematics by G. H. Hardy can be a good approach to understand Calculus made-from-scratch.

Answer 2

I think Boris Demidovich's Problems in Mathematical Analysis is a good book if you are going for the problems.

Link and reviews: amazon