Dropbox Interview Questions

Note: ensure you read the disclaimer on the previous page reading the accuracy and sourcing of these problems.

Convert Number to Words

Can you convert a number to its text equivalent? This is otherwise known as number spelling . For example, given 1234 , we expect to get "one thousand two hundred and thirty four" back. Constraints The given number will have 100 digits Let n be the number of digits E...

Difficulty: 8/10

Subsets Summing Zero

Given an array of positive and negative integers like the following: js const arr 3, 5, 2, 4, 7, 1, 6, 8, 8, 4 Can you write a method findSumZeroSubsets to return the starting and ending indexes of all subarrays in it that sum up to zero? **Note**: There are 3 terms that...

Difficulty: 7/10

Array Intersection

As we ease our way into the course, we'll want to start with the basic data structures and their operations. However, don't be fooled how fundamental these things are! Interviewers will often test you on things that are deceptively easy. We saw this in Reverse a String challenges reverse a stri...

Difficulty: 2/10

Detect Substring in String

How would you write a function to detect a substring in a string? If the substring can be found in the string, return the index at which it starts. Otherwise, return 1 . js function detectSubstring str, subStr return 1 Important do not use the native String clas...

Difficulty: 4/10

Remove Duplicates From Array

Given an array, return another array with just the ordered unique elements from the given array. In other words, you're removing any duplicates. Note: Order needs to be preserved, so no sorting should be done. And the order should be maintained with the first occurrence of the element in the given...

Difficulty: 4/10

Sum All Primes

You're given a number n . Can you write a method sumOfAllPrimes that finds all prime numbers smaller than or equal to n , and returns a sum of them? For example, we're given the number 15 . All prime numbers smaller than 15 are: 2, 3, 5, 7, 11, 13 They sum up to 41 , so sumOfA...

Difficulty: 4/10

Detect Loop in Linked List

What is the best way to find out if a linked list contains a loop? You're given the following data structure as the definition of a linked list node: js class LinkedListNode constructor val this.val val this.next null A loop or a cycle in graph less...

Difficulty: 7/10

Linked List to Binary Search Tree

We're given a sorted singly linked list that is, a linked list made of nodes with no pointers to the previous node where the elements are already arranged in ascending order. js 9 2 3 5 9 Linked List Node Definition: function Node val this.val val this...

Difficulty: 7/10

Find Shortest Palindrome Possible

We have a string str like the following: js const str "bubble" Find a way to convert it to a palindrome by inserting characters in front of it. Recall that a palindrome is defined as "a word, phrase, or sequence that reads the same backward as forward". What's the shortes...

Difficulty: 5/10

Build a Calculator

Let's build a very basic calculator by programming it! You've probably seen one that look similar to this: But we won't be building a physical calculator HardwareDaily will need to wait! instead, we'll be writing a simple program that can serve as one. Can you write a function that will evalua...

Difficulty: 7/10

Designing a Dropbox Service and Servers

Inside Dropbox Architecture Dropbox has become a staple of personal cloud storage. Like Google Drive, it offers convenient online file hosting and synchronization. But how does Dropbox actually work behind the scenes? In this guide, we'll explore the components that power Dropbox's architectur...

Difficulty: 5/10

Pursuing Deep Work Through a Slow and Boring Successful Career

Fear of Missing Out It's not a new idea that people born in the times since, or just before the digital revolution have different brains than our predecessors. We lean towards stimulation, towards a certain variability in life. We fiend for the newest, the latest, and are constantly seeking **t...

Difficulty: 5/10

Interview Reports

Intern season is quickly approaching, and we’re excited to welcome our interns to our San Francisco, Seattle, and New York offices for a summer full of activities, learning, and development. As we…