Jane Street Interview Questions

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

Max Leaps in Jump Game

We have an array that model square blocks on a city street. On each block is a non negative whole number. Ever heard of hopscotch? Picture that as an array: 1, 3, 2, 2, 1 Now, in hopscotch, you need to jump in patterns from the start to the end of the boxes. We can model that behavior in the...

Difficulty: 5/10

Serialize and Deserialize a Binary Tree

Given a binary tree representation, can you come up with a method to serialize the tree and then deserialize it to get the exact same tree? What is Serialization and Deserialization? Serialization is a process that converts a data structure to a suitable format that can be stored either ...

Difficulty: 8/10

Decimal To Binary

Today, we're going to do some math! There is only one prerequisite for answering this question, and it is knowing the definitions of binary and decimal . According to How to Convert Decimal to Binary and Binary to Decimal https: techterms.com definition binary , binary is a numeric system th...

Difficulty: 5/10

Single Lonely Number

In a given array of numbers, one element will show up once and the others will each show up twice. Can you find the number that only appears once in O n linear time? Bonus points if you can do it in O 1 space as well. lonelyNumber 4, 4, 6, 1, 3, 1, 3 6 lonelyNumber 3, 3, 9 9...

Difficulty: 3/10

Levenshtein Edit Distance

An edit distance is a way to quantify how different two strings are. This is calculated using **the minimum number of transformations to turn one string to another**. The transformations include insertion , deletion , and substitution . So when comparing two identical strings, say cat and ca...

Difficulty: 7/10

Hoisting and Call Stack

Understanding Variable Scoping in JavaScript Let's dig into a fascinating JavaScript example to unravel the mystery of variable scoping. The Code Snippet Here's the code we'll be examining: javascript var numOfBeers 5 function getMoreBeers console.log 'I have this many beers: ...

Difficulty: 7/10

K Largest Elements From List

We're given a list or array of numbers, like the following: const nums 5, 16, 7, 9, 1, 4, 3, 11, 2 Can you write an algorithm to find the k largest values in a list of n elements? If k were 3 , we'd want the three largest numbers returned. The correct logic would return 16, 11, 9 ....

Difficulty: 5/10

Stock Buy and Sell Optimization

This is a classic technical interview question that I've seen a number of times in real life interviews. Let's say you're given an array of stock prices, with each element being an integer that represents a price in dollars. 10, 7, 6, 2, 9, 4 Each index of the array represents a s...

Difficulty: 5/10

Course Prerequisites

Here's a classic challenge that comes up in real life interviews surprisingly often. Interviewers like it as a way to assess your ability to find the right data structure for a non obvious and non trivial use case. The prompt is as follows: you're a university student currently trying to plan th...

Difficulty: 8/10

Getting Your First Software Job Without Professional Experience

I ve had a few friends recently ask me about breaking into the software industry. Most have been looking for advice on getting a developer job at a consumer facing web internet company though places like Tesla and WeWork are also very popular. These friends have probably heard about the amazin...

Difficulty: 5/10

Introduction to Databases

Introduction to Databases As a senior backend engineer, you may have encountered situations where handling data efficiently and effectively is crucial. Databases play a fundamental role in managing and organizing large amounts of data. In this lesson, we will explore the theoretical concepts be...

Difficulty: 5/10

JavaScript Basics

Introduction to JavaScript JavaScript is a lightweight, text based programming language that adds interactivity to websites. It cannot execute independently, that is, it requires the support of another language HTML for execution. Here's an example of a simple JavaScript program: js con...

Difficulty: 5/10