A soft question:
Can anyone please share a list of books that contain the necessary theory -- and problem solving techniques -- to tackle the problems based on the topic of Polynomials that appear in the USAMO/IMO/Putnam?
Furthermore, how would you rate the difficulty level of the problems that in the book "Polynomials" by Edward Barbeau with regards to the problems that appear in these tests, i.e IMO and Putnam, especially the Putnam?
Thank you!