having a interview in 24 hours of 3 rounds for Intern role at statup

total time : 90 mins
interviewer : ex-Cred 8+ YOE

round 1 : personal best project discussion deep dive 20 mins

round 2 : DSA with NO AI ( I know zero DSA; no algorithms memorized ) they want to check problem-solving, data structures I use, reason and cost, and complexity

round 3 : code together with AI ( here i have confidence I will be able to debug + solve it )

I am worried about the DSA part because I don't know the basics of algorithms, and I mess up at giving reasons and hallucinate

I need suggestions on how to perform on the DSA round despite having less knowledge

my self 2026 passout; this is going to be the 5th interview of my whole CS journey