Round1[LLD]:
Design a key value store and an Index. This is frequently asked in cred, there were constraints like for one key there can be only one type, like if I have a key1 as Integer then all keys have to be Integer for key1.

Round 2[DSA +LLD]:

1. Search for an element in sorted rotated array

2. Minimum transactions to settle accounts. Some variation of Splitwise.

3. Design Red Bus Schema
   Had to consider cases where between a major route like Delhi to Bangalore, we have subroutes like Delhi to Indore , Indore to Hyderabad and Hyderabad to Bangalore.

Round 3 [HLD]
Design a system which keeps track of leaders for some contest. Like referrals leader.
I wasn't aware of CDC concept, so couldn't solve it.

Overall good interview experience.