Interview Experience of top tech companies like Directi, Swiggy, Zomato and many more

Top tech start-ups

In this article, I will be sharing my interview experiences in some of the top tech start ups. I recently made a switch from Hike Messenger where I was working in the backend team as SDE 1. I have given interviews in various start ups and have cleared almost all of them. I have a total experience of 1.5 years as of Jan 2021. Let’s dive into each of these experiences one by one

1. Zeta (Directi company)

Role : SDE 2 Backend

First Round (1hr)

It was a DS Algo round in which I was asked 2 questions of medium / hard difficulty level I guess. One was of dequeue and other was of DP on binary trees. I was able to write the complete code of the 1st question and was able to tell the approach of the second one (since the time left was very less)

Second Round (2hrs)

It was a system design round where I was supposed to design a parking lot. The interviewer checked for correctness, code readabilty and code modularity mainly and gave hints whenever I was stuck

Third Round (1hr)

This was a hiring manager round where I was first asked to explain my current company’s project’s entire architecture on which I have been working and then he cross questioned on disadvantages of using some tech stack, things related to cost optimizations etc. After that he asked some questions on redis and mongodb replication, sharding etc. Also he asked how can I implement Redis List using Redis Hash.

Fourth Round (15 mins)

It was not an interview actually, it was a normal discussion with the Director of Engineeering. He asked about my projects at Hike, tech stack that I have used and work related expectations from Zeta.

Verdict : Selected

2. Zomato

Role : SDE Backend

First Round (1.5 hours)

It was a mix of DS-Algo and some design related questions. The interviewer first asked me about database sharding and replication, why we do it, different techniques for sharding etc. Then he asked me how I used no sql databases in my current work. After that he asked me 2 coding questions. One was a medium difficulty string based question and second one was a DP question and I was able to solve both of them.

Second Round (1.5 hours)

It was again a mix of DS-Algo and System Design round. The interviewer first asked me to design a redis like cache (LLD design) keeping in mind the latency should be low for retrieval, insertion and deletion from the cache.

The she asked me 1 coding problem of medium/hard difficulty on heaps and I was able to solve that. Then she asked a bit about load balancing, cdn caching, how i used caches in my current project. Which types of databases i have used and why, different b/w sql and no-sql databases, how we store png images in caches.

Verdict : Selected

3. PocketPills

Role : SDE Backend

First Round (1hr)

I was asked 1 coding problem which was of medium difficulty and I solved that very quicky with complete code. Then the interviewer asked me the difference b/w hashmap and hashtable and after that he asked me to implement hashmap (LLD design)

Coding ques and solution which I gave:

Given an array of houses and sprinkler positions find the minimum radius such that all the houses are covered by at least one sprinkler.(all the sprinklers will have the same radius)

Houses = [1,4,7]

Sprinkler = [2,5]

Radius = 2.

Int getminRadius(int[] houses, int[] sprinklers){

Int i=0, j = 0;

Int minRadius = 0;

while(i < houses.length){

Int currentDiff = Math.abs(sprinklers[j] — houses[i]);

Int nextDiff = integer.MAX_VALUE;

if(j < sprinklers.length — 1){

nextDiff = Math.abs(sprinklers[j+1] — houses[i])

}

if(currentDiff > nextDiff){

j++;

}

minRadius = Math.max(minRadius, Math.min(currentDiff, nextDiff));

I++;

}

Return minRadius;

}

Second Round (1hr)

The interviewer asked me 2 coding problems and I was able to solve both of those. First one was a simple one -> https://www.geeksforgeeks.org/temple-offerings/ same exact question and second was a tough question on binary trees. I took somewhat more time on that but yeah I was able to write the complete code for that before time.

Verdict : Selected

4. Swiggy

Role : SDE 2 backend

First Round (1hr)

Purely DS-algo round with 2 interviewers. They asked 2 coding problems, first one was fairly simple : Sum pair problem, second problem was to print the vertical view of n-ary tree (remember not binary but n-ary tree). It was a slightly trickier problem but I was able to solve it well before time. The interview ended in 45 mins only

Second Round (1.5 hours)

Again it was DS-algo round. The interviewer asked me 2 problems, first one was to right a function to calculate a square root of a number (fairly simple).

The second was a very tricky question, although at the end the solution was not that difficult but to understand the problem was a challenge in itself.

This was the question -> https://www.geeksforgeeks.org/minimum-iterations-pass-information-nodes-tree/

At the end I was able to write code for both of these

Third Round (30 mins)

It was not an interview actually, it was a hiring manager round where the interviewer asked me about my projects at Hike. What initiatives I took to improve or optimize the existing code. Tech stack that i am aware of. Expectations from swiggy etc.

Fourth Round (1.5 hours)

It was the most exciting interview of my life and I would say the most challenging one till now. I was asked to design an e-commerce utility which does everything after the user places the order in an e-commerce app.

Basically I had to think what should happen in the background after a user places the order, which areas would be affected and what services needs to invoked by the mobile/web client.

I designed (LLD design) the following services :

1. Inventory Management Service -> The items ordered needs to be deducted from the inventory
2. Promotion Service -> If there is any promotion code applied for some cashback that also needs to invoked so that user can avail that once the order is placed (similar to what amazon does when you pay from amazon pay, they send e-mail for new coupons that are unlocked)
3. Payment Service -> Using the user’s selected payment method, underlying payment gateways / services needs to invoke and handle payment related functionalities
4. Order Tracking Service -> What happens when that order is cancelled, or checking the status of an order

This was just an overview of something very huge that happens when someone places an order on an e-commerce app

Verdict : Selected

I also gave 1–2 rounds of interviews in several other companies as well like Whitehat Jr. , Games 24 X 7, Cleartax etc. but later declined since I got an offer from one of these companies

Thank you reading till the end, hope you have liked it. Please let me know in comments if you find it useful or not.