Walmart

Role: SDE Intern + FTE

College: Not Specified (College Hiring)

Interview Date: March 2024 (Online Coding Test: 11th March 2024)

Interview Type: Internship (with FTE potential), College Hiring

Result: Selected

Difficulty: Medium

Rounds: 4 rounds (Online Coding Test, Technical Interview 1, Technical Interview 2, HR Interview)

Topics Asked: OS, DBMS, CN, DSA (character frequencies, graph problems, binary tree with mirror pointers, min distance in binary tree, stack using queues, interval merging), Projects, SQL vs NoSQL, OOP Concepts, Normalization

Experience:

This experience is for a Walmart SDE Intern role through college hiring, with a chance for a full-time offer. The process involved an online coding test, two technical interviews, and an HR interview.

Round 1: Online Coding Test (HackerEarth, 90 minutes)
The test comprised 10 MCQs (OS, DBMS, CN, DSA) and 2 coding questions.

Coding Questions:
1. Make Two Strings Equal with Swaps: Allowed to swap characters within a string or between two strings. Logic: If all character frequencies across both strings are even, strings can be made equal.
2. Unreachable Pairs After Edge Removal (Graph): Given an undirected connected graph, remove edges one by one and count (u, v) pairs that become unreachable. Key Idea: Think in reverse using DSU (Disjoint Set Union).

Round 2: Technical Interview 1 (Zoom Breakout Room, Same day, 11:00 AM)
The interview started with an introduction, past internship, and projects. Questions included: "OS in one word: User-Interface", Types of interrupts (with a hint).

Coding:
1. Binary Tree with mirror pointers: Find the minimum distance between any 2 nodes (solved using BFS).
2. What happens when you type www.google.com?
3. Network Questions: Hub vs Switch, Noise Impairment (candidate struggled).
4. SQL vs NoSQL (explained with examples).
5. Coding (Index Shifting): Right shift subarray in multiple [l, r] queries (optimized using index transformation).

Round 3: Technical Interview 2 (Zoom, Same day, 4:00 PM)
This round began with a CV summary and a project demo (GitHub video impressed the interviewer).

Coding:
1. Implement Stack using Queues.
2. Find time slots where 3 students are free (interval merging + 2 pointers).
3. What is Normalization? (Explained till BCNF).
4. OOP Concepts (live coded example with Shape, Rectangle, Square inheritance).

Round 4: HR Interview
(Details not explicitly provided in the snippet, but part of the flow).

Verdict: The candidate was selected.