Actual Coding Interview Process and How It's Different From Doing LeetCode

Coding interviews can feel daunting, especially for those who haven't done one before. You may have spent countless hours practicing on LeetCode, but the actual interview process often looks quite different. Let's break down how modern coding interviews work, what types of questions you can expect, and how interviewers typically grade you.

The Evolution of Interviews

Before COVID, interviews were often held in person (sometimes called "on-site" or "whiteboard" interviews). Companies would fly candidates in to spend a full day—sometimes more—meeting with potential teammates and managers. These days, it's a different story. Nearly all coding interviews have moved online because it's more cost-effective.

Typical Interview Outline

You'll usually meet with a senior engineer or higher-level developer from the company. They're responsible for evaluating your coding skills, communication abilities, and overall problem-solving approach.

Introduction (5 minutes)

Your interviewer will often kick things off with casual questions about your background. This is your chance to briefly talk about relevant projects, work experience, and what interests you about the company.

Coding Session

After a short chat, you'll be given a link to a coding environment. Some companies use dedicated platforms like HackerRank or CoderPad; others might opt for a simple shared document (like Google Docs) to simulate a whiteboard experience.

Wrap-Up and Questions

If time permits, you might get a few minutes to ask questions about the role, the team, or the company. Use this opportunity to learn more about what they're looking for and if it aligns with your career goals.

What Questions Will You Be Asked?

Larger tech companies often use LeetCode-style questions. Usually, the problems tagged on LeetCode for each company are pretty accurate. We recommend first learning all the patterns and being able to write bug-free code and then working through the top company-tagged problems.

Smaller or mid-sized companies might not have a huge pool of proprietary questions. They commonly rely on the popular "Blind 75" list (or similar collections of essential coding interview problems), so doing all of those will cover you in the majority of cases; and even if not, most other questions are derivatives of these questions, so you'll probably still be able to figure them out.

If you have an interview coming up, check out our company-specific interview guide for the latest questions and tips.

Interview Process

Here is the process for which you should solve these problems:

Read the question and understand it - ask your interviewer thoughtful questions. Some information is usually left out intentionally to see if candidates are actually thinking.
Mention things like edge cases to watch for, important constraints, etc.
Verbally state all ideas for how to solve it - your interviewer wants to know that you can come up with multiple ideas.
Think out loud - your interviewer can't help or judge you if they can't tell what you're thinking.
Pick the best idea and justify why you chose it - this is usually based on time and space complexity, but whatever the reason is, you need to say why you think it's the best choice.
Your interviewer will either say "yeah this is a good idea, get started coding it" or say "hmm maybe not" and give you a hint about different approaches
Start coding your chosen solution, and most importantly, talk as you code.
Don't worry if you forget small syntax things, the interviewers will help you out and sometimes even let you use the internet - what's important is that your approach is correct.
At the end, run some test cases - if you're on a platform that can run code, write your tests out; if you're on a simple text editor, manually do a trace through your code.

Here's a mock interview that shows how it works and what to look out for:

Actual Interview ≠ LeetCode

As seen in the video, there are quite a few differences between practicing on LeetCode and doing an actual interview. Here are the most important ones:

You are not provided test cases, you need to provide the test cases yourself; however, don't worry about catching the extreme edge cases that LeetCode sometimes has, interviewers don't ask about these.
You often won't be running the code, so it doesn't matter if you "beat X% of users" like on LeetCode; but you need to walk through test cases manually when you're done.
Communication is very important, your interviewer needs to know your thought process so they can see how you work through problems.
Document your code, as this gets saved and reviewed with the interview committee.

If you're practicing on LeetCode, the main takeaway is to focus on getting the correct approach and demonstrating your problem solving skills.

How You're Graded

Most companies give their interviewers a rubric to grade candidates on. While rubrics can vary from company to company, they often include:

Understanding of Data Structures and Algorithms

Do you know how to apply the right tools to solve the problem? Are your time and space complexities reasonable?

Autonomy

Can you work through problems on your own, or do you need constant hints? A candidate who can find logical next steps independently tends to score higher.

Communication

Are you articulating your ideas clearly? Good communication is essential in a collaborative environment.

Code Organization

Is your solution clean, readable, and well-structured? Interviewers often check if your code can be easily understood and maintained.

How to Prepare

Again, check out the mock interview above to see how it works if you haven't already. The takeaways are:

Patterns are the most important thing to focus on. This is the core of what AlgoMonster is all about.
You should strive for bug-free code at first shot. This is where our templates come in. There are often more than one way to "skin a cat" (sorry for the wording here, I love cat, but you get the idea), but some implementations are easier to get right and harder to make mistakes. Our templates are designed to be the easiest to get right.
Real interviews are different from LeetCode. You will be asked to code in a Google Doc or a simple editor where you likely don't have to run the code. So there is no point in beating the LeetCode leaderboard or trying to exhaustively test your code with every edge case possible. The time should be spent on thinking through the problem and communicating your ideas. This is where seeing more problems is super helpful. We have a feature for this, called Speedrun. In this mode, you don't actually code the problem, but instead you are asked to answer a multiple-choice question about the problem. This is a great way to see more problems quickly. Instead of spending 30 minutes on one problem, you can see five to ten problems in that time.

Now that you have a good idea of how the interview process works and the importance of patterns, let's talk about how you can make your study the most effective. This includes how to use AlgoMonster, how to use other resources, and how to make the most out of your study time and the psychological aspect of it.