there are a few books you can get: https://www.amazon.com/gp/product/1565923987/ https://www.amazon.com/gp/product/1565923987/ https://www.amazon.com/dp/0262033

there are a few books you can get: https://www.amazon.com/gp/product/1565923987/ https://www.amazon.com/gp/product/1565923987/ https://www.amazon.com/dp/0262033844/ https://www.amazon.com/dp/0262033844/ A lot of "classic" problems are so embedded into CS professors that they don't even see them as problems anymore (lazy caterer, pick's theorem, etc) so if you didn't study these classics explicitly in school you have to discover them on your own.