Although they're not common nowadays, the 7400 series includes some more highly integrated parts, including a complete ALU. There's no exact criteria for what "discrete logic" means, but I don't think anybody would accept a complete integrated ALU. To me, it means things like gates, multiplexers, or flip-flops: things that can be made with a few tens of transistors at most.

"Discrete logic" computers usually use integrated RAM chips, but seeing as RAM is usually drawn separately from logic on block diagrams, I think this is still acceptable. However, the popular trick of using an EEPROM as a giant lookup table for your ALU is in my opinion not "discrete logic".