Blinkit · Mid — 2 rounds, graph algorithms + LLD, rejected

Round 1 — Graph Algorithms & System Concepts

After introductions and discussing my current project, I was asked:

Problem: Given a weighted directed graph with a source and destination, you have a set of edges and can add at most one edge. Find the minimum possible distance from source to destination.

Constraints: Expected time and space complexity of O(E * log V).

I solved this with a hint from the interviewer, but we ran out of time before I could code it.

The interviewer then asked about cache advantages. After I explained it's used for faster retrieval, he followed up: "Assume we have infinite cost. Why can't we just replace a database with a cache?"

I wasn't able to answer this question.

Round 2 — Low-Level Design

After introductions and a project discussion, I was asked to design an LLD for a movie ticketing system (similar to BookMyShow).

I spent too much time discussing my project and wasn't able to complete the LLD. I felt I could have performed better on this question overall.

Outcome: Rejected