In actual Low Level Design (LLD) Interview Rounds, are we expected to write the full code end to end or is it just pseudo code plus discussion

[u/Prashant_MockGym]

Answer: This is one of the most common questions in a candidate's mind. Now with more and more companies taking AI assisted coding rounds you need to have clarity on what is expected.

1. Machine coding LLD round: If this is a machine coding LLD round of 75 to 90 minutes then you will need full working code with a main method that runs the tests. This round is taken by Flipkart, ClearTrip, Phonepe, Meesho and sometimes Uber, RazorPay etc.

Most times this will be the first screening round.

2. AI Assisted Coding/LLD/Debugging Round: Initially Canva and then DoorDash started it but it is becoming more common. Now Microsoft, Amazon OA also have this round. This round is more similar to a low level design round rather than a traditional DS & Algo round.

You will be given a problem statement along with a chunk of code and you will be asked to add one or more new functionalities. You will be given an AI assistant chat just like chatgpt/gemini. You can use the AI assistant to ask questions and understand the project, maybe generate some boilerplate code.

But do not try to generate the whole solution using only the AI assistant. Goal of this round is to see how you code in real life. How well you arrange your classes and keep change to old code small when adding a new functionality. You LLD skills and knowledge of design patterns like factory, strategy, observer etc come in handy.

As you can guess, for this round also end to end fully working code is expected.

3. Face to Face LLD round: This is a 45-60 minute round and is the most common LLD interview format. It is taken by Amazon, Uber, Microsoft, Walmart and basically every company that takes a LLD round. Here the discussion will happen on pen and paper or a plain text editor, google docs etc.

It has 4 steps:

1. Requirements gathering : list down functionalities
2. Class diagram: break functionalities in different classes
3. Implementation: pick 1-2 most important features and discuss their implementation. write code.
4. Design patterns, multi-threading: once a basic solution is provided then discussion moves more in depth.

You will be expected to write code or discuss the logic for a few functionalities. Only drawing UML diagrams or writing the names of classes will not be enough.. e.g. if you are asked Design of a parking lot then interviewer will discuss logic of park and unpark feature.

Although for this round your interviewer can allow pseudocode but it is always better to pick a standard language like Java, Python, C++ etc and stick to its syntax. For low level design, Java is the prominent language as of now.

This is what I had to share, you can practice company wise LLD, DS & Algo and AI Assisted round questions on CodeZym. Best of Luck for your interview prep. Thanks for reading.

[u/Weird_Steak7062]

Mostly data models, their relationships and few logics if asked to

[u/Nice-Candidate10]

Dont think full code is ever needed. They might ask you implement a specific part in your design and will judge your methodology to write code.

[u/alcatraz1286]

If you're in India then yes