Infosys L3 Interview Experience - Out of Campus (HackWithInfy)
Summary
I attended an Infosys L3 interview that consisted of a resume review, a DSA question (LRU Cache), a system‑design LLD (movie booking service), and SQL questions; I didn’t solve everything completely and am awaiting the result (later selected for DSE with 7 LPA).
Full Experience
For the interview, these were some of the common questions they asked:
- Jump Game
- LRU Cache
- Swap Nodes in Pairs
- Find the Closest Palindrome (+ follow‑up: find the strictly greater palindrome number)
If you are interviewing for L3, your interview will most likely be divided into two parts:
- Resume Review (30–45 min):
They ask questions based on your resume, past experience, and some light problem‑solving questions. It’s not too difficult if you’ve revised your resume, even loosely.
*[This round is for everyone, and L1 candidates only need to clear this.]* - DSA + System Design + Deep Dives (30–45 min):
They started with a brief introduction and then gave one DSA question (in my case, it was LRU Cache). I didn’t know the complete solution, so they guided me with hints, but I still couldn’t solve it fully. They also asked a very open‑ended LLD question to design a movie booking service.
This is also the round where they may dive deep into your resume if you have something interesting listed. They can ask detailed questions on OS concepts, networking, memory management, and the internal workings of your programming language.
*[This round is only for L2 and L3 candidates.]*
Some Important Things to Note:
- SQL is a good part of these interviews, I was asked SQL in both the rounds with varying difficulty. LeetCode's SQL study plan is enough but also brush‑up the insertion, updating and deleting values from a Table, online SQL platforms don't include those.
- The environment is very fast‑paced. They interview more than 100 candidates in a single day, so everything feels rushed. You need to be both accurate and quick while solving problems.
- This interview pattern is not fixed. If the L1 interviewers are busy, you may be directly assigned to L2/L3 interviewers. Be prepared to jump straight into DSA questions.
- The interviewers sit in separate cubicles, and candidates are invited one by one. Most interviewers tend to ask similar(same) questions to different candidates, so if you are strategic enough, you might get lucky.
Closing Thoughts
My interview itself didn’t go very well, there were too many fumbles. But the results haven’t been announced yet, so I’ll update the post once they are.
And well, good luck, guys.
Update
I got selected for DSE which offers 7LPA.
Interview Questions (4)
Jump Game
Given an array of non‑negative integers where each element represents your maximum jump length at that position, determine if you can reach the last index.
LRU Cache
Design a data structure that follows the constraints of a Least Recently Used (LRU) cache. Implement get and put methods with O(1) time complexity.
Swap Nodes in Pairs
Given a singly linked list, swap every two adjacent nodes and return its head. You may not modify the values in the list's nodes, only the nodes themselves may be changed.
Find the Closest Palindrome
Given a numeric string, return the closest palindrome number (excluding the number itself). Follow‑up: find the strictly greater palindrome number.
Preparation Tips
I prepared by reviewing LeetCode’s SQL study plan, brushing up on insertion, updating, and deleting operations, and practicing DSA problems such as Jump Game, LRU Cache, Swap Nodes in Pairs, and Find the Closest Palindrome.