Top 16 TikTok Machine Learning Engineer Interview Questions + Guide in 2024

What sets TikTok apart as a premier platform for short-form video content distribution? The answer lies in the innovative design of TikTok’s “For You” page. This feature presents a meticulously curated stream of videos, each selected by the platform’s advanced machine learning algorithm. It also serves as TikTok’s flagship feature.

As key stewards of the “For You” page, machine learning engineers at TikTok play an important role in determining the company’s success. This gives ML Engineers a unique impact on the company’s future, and presents both opportunities and challenges for anyone looking to jump into that role.

Let’s explore the interview process together for this role, highlighting the top 16 Tiktok Machine Learning Engineer interview questions and how to ace them!

Application and Online Assessment

Start your journey by applying directly on TikTok’s career site. After applying, you might be invited to complete a HackerRank Online Assessment. This typically consists of five questions including two multiple-choice questions, one medium coding question (data structures), and two hard dynamic programming questions.

Per some candidates, the provided helper code might have errors that need fixing before you can start solving the problems. Also, be sure to brush up on data structures and algorithms, particularly dynamic programming and graph theory, before attempting the questions.

Multiple Rounds of Interviews

If you pass the online assessment, you will proceed to one or more interview rounds focusing on machine learning and your previous projects. These interviews might involve logistics regression problems and coding questions.

The interviewers might be interested in the details of your past machine learning projects and could quiz you about them beyond surface-level knowledge. Along with those topics, they will test you with algorithm and data structure questions.

Behavioral Question Rounds

Lastly, there might be a behavioral questions round which mainly includes walking through your resume, discussing one of your projects, and a coding test.

At TikTok, a Machine Learning Engineer interview is designed to rigorously assess a candidate’s proficiency across several technical domains. These interviews typically delve into areas fundamental to the role, such as:

• SQL
• Coding and Algorithms
• Machine Learning
• Analytics and Experiments
• Statistics and Probability

Here are some questions you might encounter in your interviews.

1. Write a query to find the average quantity of each product purchased per transaction each year.

Given a table of transactions, write a query to find the average quantity of each product purchased per transaction each year. The output should include the year, product_id, and average quantity of the product purchased per transaction that year. The output table should be sorted by year and product_id in ascending order. The value for avg_quantity should be rounded to two decimal places.

2. Create a query to get the total amount spent on each item by users that registered in 2022.

Assume you work at Costco. Costco has a database with two tables. The first is users composed of user information, including their registration date, and the second is purchases that has the entire item purchase history (if any) for those users. Write a query that returns the total amount spent on each item in the purchases table by users who registered in 2022.

3. Write a query to get the post success rate for each day in January 2020.

Consider the events table which contains information about the phases of writing a new social media post. The action column can have values post_enter, post_submit, or post_canceled for when a user starts to write (post_enter), ends up canceling their post (post_cancel), or posts it (post_submit). Write a query to get the post success rate for each day in January 2020. Assume that a single user may only make one post per day.

4. Write a function to calculate the sum of every digit in a given floating-point number string.

You are given a string that represents a floating-point number. Your task is to write a function, digit_accumulator, that returns the sum of every digit in the string.

5. Write a function to find all positive integer pairs for a given mathematical function within a specified interval.

Let $f(x, y) = 5x \cdot 3y$ Given an interval $[L, R]$ and some integer $N$ , write a function, get_possible_values, that returns all positive integer pairs $(x, y)$ such that $f(x, y) \in [L, R]$ and $x, y < N$ .

6. Write a SQL query to show the monthly report for the number of users, transactions, and total order amount in 2020.

You have transactions, products, and users tables. Your task is to write a query to show the number of users, number of transactions placed, and total order amount per month in the year 2020.

7. Which model would you choose between: one with 85% accuracy or one with 82% accuracy?

We have two models: one with 85% accuracy and one with 82%. Which one would you pick and why?

8. How would you improve a classification model suffering from low precision in predicting customer purchases on an e-commerce platform?

You’re tasked with building a classification model to determine whether a customer will buy on an e-commerce platform after making a search on the homepage. Your model is suffering from low precision. How would you improve it?

9. How would you evaluate the success of advertising for an event based on a weekly 10% increase in search clicks?

You are in charge of tracking the success of advertising for an event. Every week, there has been about a 10% increase in search clicks for the event. Is this good or bad? How would you evaluate whether the advertising needs to improve?

10. Is there a problem with an A/B test that shows one significant result out of 20 variants?

Your manager has run an A/B test with 20 different variants and claims that one of the variants is significant. Evaluate the validity of these results.

11. How would you design an A/B test to optimize button color and position for higher click-through rates?

A team wants to A/B test various changes in a sign-up funnel. For instance, on a page, a button is red and at the top. They want to see if changing the button’s color to blue and/or moving it to the bottom will increase click-through rates. How would you set up this test?

12. How would you interpret a .04 p-value in an A/B test for a landing page feature?

Your company is running a standard control and variant AB test on a feature to increase conversion rates on the landing page. The PM checks the results and finds a .04 p-value. Assess the validity of this result.

13. What is the probability of finding a specific item on Amazon’s website given its availability in different warehouses?

In a city, Amazon has two warehouses, A and B. The probability that a specific item X is available at warehouse A or B are 0.6 and 0.8 respectively. Determine the probability that item X would be found on Amazon’s website.

14. How would you explain the concept of a p-value to a non-technical person?

You need to explain what a p-value is to someone who does not have a technical background. How would you simplify this concept?

15. Write a query to show the number of users, number of transactions placed, and total order amount per month in the year 2020. Assume that we are only interested in the monthly reports for a single year (January-December).

This question gives us three tables (transactions, products, and users) and asks us to compute the number of customers, transactions, and the total monthly order amount.

You might think, off the bat, that we’ll have to join all three of our tables together in order to solve the question, but actually, we’re only going to require two. That’s because our transactions table already contains a user_id field and there’s no information native to the users table that we’ll need to answer the question.

16. You are given a string that represents some floating-point number. Write a function, digit_accumulator, that returns the sum of every digit in the string.

This question presents us with a string that represents a floating-point number and asks us to write a function, digit_accumulator, that returns the sum of every digit in the string.

At first glance, you might think that we need to consider the entire structure of the floating-point number, including the decimal point, but actually, we can simplify our approach by focusing solely on the digits. The decimal point and any other non-digit characters can be ignored since they don’t contribute to the sum. Our function should loop through each character in the string, check if it’s a digit, and then accumulate the sum of those digits.

Preparing for a Machine Learning Engineer role at TikTok demands a combination of sharpened technical skills and a deep understanding of the company’s unique platform. Here are some preparation tips:

Deepen Your Machine Learning Knowledge

Understand TikTok’s Algorithm: Familiarize yourself with how TikTok’s “For You” page works and the machine learning principles behind it. Knowing how content recommendation algorithms operate will be beneficial.

Review Core Concepts: Refresh your knowledge in machine learning, especially in areas like classification, regression, clustering, and neural networks.

Enhance Your Coding Skills

Practice Coding Problems: Focus on data structures, dynamic programming, and graph theory, as these are often emphasized in TikTok’s coding interviews.

SQL Proficiency: Be comfortable with writing complex SQL queries, as you may face questions related to data manipulation and retrieval.

Work on Projects

Hands-On Experience: Engage in personal or open-source projects that demonstrate your ability to apply machine learning concepts. Be ready to discuss these projects in detail during the interview.

Prepare for Behavioral Questions

Reflect on Past Experiences: Be prepared to discuss your resume in-depth, focusing on your problem-solving approach, teamwork, and project outcomes.

Mock Interviews

Practice Interviews: Engage in mock interviews to get comfortable with the format and type of questions asked. Try out Interview Query’s mock interviews to get a sense of the real thing.

The salary structure for a Machine Learning Engineer at TikTok typically spans a broad range. The total annual compensation for this role can range from approximately $183,000 to $270,000. Within this package, the base salary itself constitutes between $135,000 and $181,000 per year.

In addition to the base pay, there is an additional component that might range from $48,000 to $89,000 annually. It’s important to note that the most likely range of salaries indicates that the majority of the compensation packages fall within these limits, although exact figures can vary depending on factors such as the individual’s experience, specific job location, and unique role responsibilities.

As you prepare for a Machine Learning Engineer role at TikTok, remember the importance of a balanced approach that combines technical prowess with an understanding of the company’s unique platform and audience. We wish you the best in your interview preparations.

For further guidance, explore other position guides and the main TikTok Interview Guide. Additionally, consider engaging with professional services for mock interviews or resume reviews to bolster your chances of success.