Walmart Lab On-Campus Interview Experience

Round 1: It comprised of one coding question and twenty-eight mcqs on hackerearth. The coding question goes like-> You have a string of length n and given q queries. In each query, you will be given a length k and you have to find the first index of a special substring of length k.  A special substring is a substring which hasn’t repeated itself.

The mcqs were equally distributed among ds&algo, os, dbms, networking and logical reasoning. The time given was 90 mins.

14/140 people cleared this round.

Round 2: This was a technical round. While I was asked questions from os, dbms and data-structures only, few people were also asked to code a given algorithmic problem on paper. The interviewer was interested in whether I knew about the real-life applications of dynamic programming, greedy algorithms and he asked me to give a few examples for the same. In OS, the questions were from memory management like paging, segmentation, semaphores and deadlocks. Here also he was interested in real-life applications of paging and semaphores. Coming to DBMS, he asked questions from concurrency-control mechanisms and acid properties. In ds, the questions were from binary tree and hashing. Here also he tried to relate these to their practical usage. He asked me a puzzle at the end ->  https://www.geeksforgeeks.org/puzzle-6-monty-hall-problem/

9 people were selected from this round.

Round 3: I was asked 3-coding problems and asked to write the code on paper.

Problem 1-> https://www.geeksforgeeks.org/lowest-common-ancestor-binary-tree-set-1/

Problem 2->https://www.geeksforgeeks.org/reverse-a-linked-list/

Problem 3->https://www.geeksforgeeks.org/number-of-unique-bst-with-a-given-key-dynamic-programming/

Questions asked from other candidates:

https://www.geeksforgeeks.org/maximum-size-sub-matrix-with-all-1s-in-a-binary-matrix/

A question similar to  https://www.spoj.com/problems/FARIDA/

A question similar to https://www.geeksforgeeks.org/find-the-point-where-maximum-intervals-overlap/

A question similar to https://www.geeksforgeeks.org/maximum-sum-subarray-removing-one-element/ . The modification was instead of removing one element, you can square one of the elements.

For the third problem, he was just interested in knowing the approach. I didn’t hastily tell him about the catalan number approach. I first told him about the dp approach and he was happy with the answer and later on, I added catalan number to my answer.

In this round, few of the candidates were also asked about the projects they did, oops concepts, os and dbms.

Round 4: Managerial Round

I don’t have enough to say about this round. I think just being honest will do. The questions were about the projects that I did, the programming languages I know and other questions such as what would I improve in myself, the toughest situation I have been through etc…

Round 5: HR Round

I think this round was all about remaining calm and honest.

Finally, they selected 4 students and I was one of them.

PS: At the end of every round, I was asked “If I am having any questions for them”. I think this is important as it will help you create an impression of you being interested in the company so do prepare for it.