Resume Grilled , Some Design Related questions , Questions on Redis

Q1 - Check if there is a loop in a linked list. Return a boolean value.

Example:
1 -> 2 -> 3 -> 4
| |
4 <- 5
Response: true

Similar to this Question - https://leetcode.com/problems/linked-list-cycle/description/

Q2 - PRINT ALL THE SUBSETS OF THE FOLLOWING ARRAY
Arr = [A,B,C] ->
RESPONSE: A , B, C, AB, BC,CA, ABC

Q3- https://leetcode.com/problems/all-nodes-distance-k-in-binary-tree/description/

Design Question:

Consider a situation where you are working in Paytm Recharge section and you want to send notification to the user if you MB is very low eg if you have 1.5 GB and your data is around 50MB left you have to send notification to the user your MB is low.
Scale to consider - 100M Notification / per day
Database Design to consider : Store 100M writes / per day

Also you have to do analytics on top of the database.

Edit: 1
Verdit : Selected

Round 2: https://leetcode.com/discuss/interview-question/5784297/Paytm-oror-Senior-Software-Engineer-oror-September-2024-oror-Round-2
Round 3: https://leetcode.com/discuss/interview-question/5812902/paytm-senior-software-engineer-september-2024-round-3