Dropbox Interview Questions

Dropbox is a leading cloud software solutions provider and has been ranked as one of the most valuable startup firms in the world. Its $10 Billion+ valuation makes it an attractive place for software engineers and developers who wish to work in a stimulating environment, lock attractive compensation packages, and scale up their professional careers.

Dropbox’s technical interview is no different from interviews at FAANG and other tier-1 companies. If you’re an experienced engineer who wishes to land an offer at Dropbox, you have to be right up there with your problem-solving skills.

Dropbox interview questions can be fundamentally split into three broad categories — questions on algorithms and data structures, questions on distributed systems design, and questions on behavioral and psychological attributes.

In this article, we’ll understand the technical interview process at Dropbox, some sample Dropbox interview questions across categories, and some formidable tips to crack the Dropbox technical interview. We’ll cover:

• Software engineer levels at Dropbox
• Dropbox interview process and timeline
• Tips to crack the Dropbox technical interview
• Up-level your career by landing offers at the biggest companies

?Software Engineer Levels At Dropbox

Dropbox classifies its engineers based on their level of seniority.

Software Engineer levels start from IC-1 (entry-level software engineers) to IC-7 (Senior Principal Engineer).  Compensations can start from $138K for entry-level engineers and overshoot $800K for Senior Principal Engineers.

?Dropbox Interview Process

The interview process at Dropbox, starting from the Initial Screen to landing the final offer, lasts roughly 1-2 months. The process broadly comprises three rounds.

?1. The Initial Pre-Screen

If your resume is shortlisted for the role, you’ll be contacted by a recruiter who’ll ask you basic questions about your experience and skills in general. You can expect a couple of behavioral questions like:

a) Why do you want to work at Dropbox

b) What about working with Dropbox excites you the most

c) What’s the biggest news you’ve read about Dropbox lately?

You’re not asked technical questions during the Initial Pre-Screen. If your answers are satisfactory and your profile satisfies the expectations of the role, you’re invited to the next round — The Technical Phone Screen.

2.  The Technical Phone Screen Interview

The Technical Phone Screen is the first real test of your Dropbox interview. It typically lasts 30-45 minutes, during which you’re asked to solve a coding problem or two on algorithms and data structures.

In this round, your overall approach to problem-solving is carefully evaluated. You’ll be asked to brute force the solution before proceeding to write the code. Note that you aren’t given points only for getting the solution right. Your analytical analysis and ability to think from multiple solution angles are key too.

Upon clearing the Technical Phone Screen, you’re invited to the On-site Interview.

3. On-site Interview

The on-site interview at Dropbox consists of three main rounds. However, the number of actual rounds can vary depending on the seniority of the position.

The three rounds include:

1. The coding round, where you’re asked to solve 1-2 problems on core data structures and algorithms.
2. The design round, where you’re asked to design an arbitrary system and discuss its scalability, latency, and security aspects.
3. The behavioral round, where you’re assessed if you’re the right fit through questions about behavioral conduct at the workplace, past situations, work-life balance, relationships with colleagues, and the company’s culture, among other things.

As mentioned, there can be additional rounds depending on the position and level you’re applying to. Levels IC-5 and above usually have an additional design round, while IC-1 to IC-4 can have additional coding rounds. Essentially, there’s more focus on the design aspect for senior positions and an increased focus on the coding aspect for junior engineering roles. While this is the case, you’ll still very much be asked a coding question or two even if you’re interviewing for higher band levels.

4. Domain Interview

Based on the specific domain you’re applying to, your on-site will have a round where hiring managers evaluate your domain knowledge. For instance, if you’re applying for a Machine Learning role, or a role specific to a certain product or service of the company, you can expect questions around domain concepts.

Similarly, if you’re applying to a Front End Developer role, you can expect questions around front-end development in the domain interview. This is additional to the coding, design, and behavioral rounds in your interview.

Dropbox Interview Questions

Dropbox Interview Questions can be divided into coding interview questions, design interview questions, behavioral interview questions. Let’s look at each of these questions one by one.

Dropbox Coding Interview Questions

Coding interview questions are based on the following topics:

• Arrays, strings, and linked lists
• Sorting algorithms — quicksort, merge sort, heap sort, etc.
• Hash tables and queues
• Recursion
• Trees and graphs
• Graph algorithms, including greedy algorithms
• Dynamic programming

At the interview, you can expect a larger percentage of questions around Trees (Binary Trees and Binary Search Trees), Arrays, Graphs (Greedy Graph Algorithms), and Dynamic Programming.

Problems that are asked at the Dropbox interview:

1. Given an integer array arr of size n, find all magic triplets in it. A Magic triplet is a group of three numbers whose sum is zero. (Click here for solution)
2. Given a binary tree “T,” write a code to generate the mirror image of the tree. (Click here for solution)
3. Given a variety of coin types defining a currency system, find the minimum number of coins required to express a given amount of money. Assume an infinite supply of coins of every type. (Click here for solution).
4. Given a partially filled two-dimensional integer array, fill all the empty cells such that each row, each column, and each 3 x 3 subgrid (as highlighted below by bolder lines) has every digit from 1 to 9 exactly once. (Click here for solution)
5. Given a string s containing a set of words, transform it such that the words appear in the reverse order. One or more spaces separate words in s. (Click here for solution)
6. Given an unsorted set of numbers from 1 to N with exactly two missing numbers, find those two missing numbers. (Click here for solution)
7. You are given an array of integers, arr, of size n, analogous to a continuous stream of integers input. Your task is to find K largest elements from a given stream of numbers. (Click here for solution)
8. Given a sequence, return its next lexicographically greater permutation. If such a permutation does not exist, then return it in ascending order. (Click here for solution)
9. a) Given A Graph, Build A New One With Reversed Edges b) Given a strongly connected directed graph, build a new graph with the same number of nodes but every edge reversed. This is also called transposing a graph. (Click here for solution)
10. Implement an iterator over a binary tree with integer values. Your iterator will be initialized with the root node.
    1. next() method must return the next number in the in-order traversal of the tree.
    2. hasNext() method must return whether the next element exists. (Click here for solution)

Looking for more practice problems to nail technical interviews in 2021? Check out Interview Kickstart’s Problems page.
If you wish to brush up on core concepts that feature in coding interviews, visit the Learn page.

Dropbox Systems Design Interview Questions

The on-site interview will have a systems design round, where questions will be similar to the following:

1. Design a database system that stores information in its memory and processes it without lags and latency.
2. Design an IP blocking system that blocks IPs from certain locations.
3. Design a voting system where people can cast their votes by viewing candidate details, and the final votes are tallied.
4. Design an e-commerce system to find the 50 top-selling products in the last one hour.
5. Design an online bookstore that allows users to view prices and make purchases through multiple means (debit/credit etc.)
6. Design a system where an office administrator knows how many people are present on each floor of the building, given that the building has three floors
7. Design a system to upload images with tags — users would be able to visit and search for images by entering the tags.
8. Design a notification service that can send notifications to multiple users/devices
9. Design a Chatbot service that intelligently interacts with users and addresses their queries based on specific keywords.
10. Design a scheduler service that can manage huge schedules with no lag and minimal latency

Dropbox Behavioral Interview Questions

Behavioral interviews are an extremely important part of the hiring process at Dropbox. Below are some behavioral questions to help you prepare for Dropbox’s interview.

1. Tell us about a time when you were stressed because of a demanding project? How did you go about the situation? What are the ways in which you handle workplace or work-related stress?
2. Describe a time when you had a difficult relationship with your superior/manager. How did you deal with the situation?
3. Describe a time when a client was particularly difficult to handle? What was your course of action?
4. Tell us about a time when a colleague was uncooperative, and the progress of the project was being interrupted due to it. How did you deal with the situation?
5. How do you ensure to maintain high productivity levels at work?
6. How do you generate excitement at work when your daily tasks sometimes become monotonous?
7. Tell us about a time when you missed a project deadline? What was the reason, and how did you deal with it?
8. Tell us about a time when you had to make an important decision with little available data?
9. Tell us about how you strike the right work-life balance amid a challenging and stressful project?
10. Give us an example of how you set goals and prioritize them?
11. Tell us about a time when you had to be adaptable and flexible for a particular project? Were there new learnings involved?
12. Tell us about a time when a certain project went south a little too late, and you had to restart again.

For more behavioral interview questions asked in software developer interviews at FAANG and tier-1 companies, check out these behavioral questions for software engineers.

Tips to Crack the Dropbox Technical Interview

A strategic plan and lots of hard work are key to cracking tech interviews at tier-1 tech companies like Dropbox. The following tips will help you craft the right plan and nail your next Dropbox interview:

• Your prep timeline should be 10-12 weeks. Giving your interview before you’re thoroughly prepared is tantamount to disaster. Covering the length and breadth of technical topics takes at least 8-10 weeks, even if you’re a smart coder. So if you want to make sure you’re extensively prepared, give yourself sufficient time.
• Practice whiteboard coding. The on-site interview might sometimes require you to code on a whiteboard in the coding round. Whiteboard coding exposes shortcomings in analytical abilities and also ups the pressure quotient, putting even experienced programmers to the test.
• Practice problem-solving through pattern identification: Approach problem solving by identifying patterns in problems and applying similar patterns to solutions for new problems. Try and practice at least a hundred problems of varying difficulty.
• Think out your solution aloud: In the interview, you’re awarded points for the way you arrive at the solution, not just for getting it right. It’s important to clarify your doubts and ask questions when you’re deadlocked. Recruiters preferably like to hire candidates who know what they’re doing while solving a problem.
• Practice mock interviews. Practice with hiring managers from FAANG companies to get a better sense of what to expect at technical interviews and how you should tune your skills to get past the grueling interview rounds at top companies.

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