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".
"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".