What is the difference between Sushupti and Samadhi with respect to the state of the mind? Would it be correct to say that the intellect or buddhi is active in Samadhi and dormant in Sushupti?
Chitta will be active in samadhi; (That is why one can remember the experience of being in samadhi, later)
Ahankara (and chitta) will be active in sushupti (So that one can say that 'I' had a good sleep, later)
Buddhi is the decisiveness faculty- predominant only in jagrat avasta.
Does chitta mean memory here?
Yes.
Ok. I am still not entirely clear about this
Sushupti - I had a good sleep
Samadhi -I was in Samadhi
We need the 'I' in Samadhi as well. isn't it? If not, then who was in Samadhi..whose state is stored in the chitta?