Cockroach Labs Interview Questions

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

String From Binary Tree

Suppose we're given a simple binary tree lessons an intro to binary trees and search trees like the following: js 1 2 3 4 Can you **generate a string** based off the values of its nodes? With this string, we're going to want to capture ...

Difficulty: 5/10

Sum Digits Until One

We're provided a positive integer num . Can you write a method to repeatedly add all of its digits until the result has only one digit? Here's an example: if the input was 49 , we'd go through the following steps: start with 49 4 9 13 since the previous addition was 13, move ont...

Difficulty: 4/10

Max of Min Pairs

We have an array of length 2 * n even length that consists of random integers. 1, 3, 2, 6, 5, 4 We are asked to create pairs out of these integers, like such: 1, 3 , 2, 6 , 5, 4 How can we divide up the pairs such that the sum of smaller integers in each pair is maximized? ...

Difficulty: 4/10

Reverse a Linked List

You're sent a linked list of numbers, but it's been received in the opposite order to what you need. This has happened multiple times now, so you decide to write an algorithm to reverse the lists as they come in. The list you've received is as follows: 7 2 21 6 42 10 Write ...

Difficulty: 6/10

Zeros to the End

Write a method that moves all zeros in an array to its end. You should maintain the order of all other elements. Here's an example: js zerosToEnd 1, 0, 2, 0, 4, 0 1, 2, 4, 0, 0, 0 Here's another one: js zerosToEnd 1, 0, 2, 0, 4, 0 1, 2, 4, 0, 0, 0 F...

Difficulty: 5/10

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

Fibonacci Sequence

Implement a function that returns the Fibonnaci number for a given integer input. In a Fibonacci sequence, each number is the sum of the two preceding ones. The simplest is the series: 1, 1, 2, 3, 5, 8, etc. This is because: fibonacci 0 0 fibonacci 1 1 fibonacci 2 1 fibonacci 3 ...

Difficulty: 4/10

Add Linked List Numbers

We're provided the following two linked lists: 1 2 3 4 and 2 5 8 Each one represents a number in reversed order, so 1 2 3 4 represents 4321 and 2 5 8 represents 852 *note: for an extra challenge, consider if they weren't reversed* . The lists are guarante...

Difficulty: 7/10

Sum Right Side Leaves

Finding the Sum of Right Leaves in a Binary Tree Imagine a family tree, but instead of tracking your relatives, it's tracking numbers. Each "person" in this tree has at most two "children," and some have none. We call these childless nodes "leaves," and your task is to find the sum of leaves that...

Difficulty: 7/10

Hash Tables

Welcome to the introduction of hash tables in the Hash Tables tutorial! In this lesson, we will explore the concept of hash tables, a data structure that allows for efficient retrieval and storage of key value pairs. Hash tables provide fast access to data by using a technique called hashing. Hash...

Difficulty: 5/10

Trees

Introduction to Trees Trees are hierarchical data structures that have a root node and contain child nodes. In programming, trees are used to represent relationships and hierarchies between data elements. They are particularly useful in the fields of robotics and computer vision due to their ab...

Difficulty: 5/10

JavaScript Basics

Introduction to JavaScript JavaScript is a versatile programming language that plays a critical role in frontend web development. It allows you to create interactive and dynamic elements on web pages, making them more engaging for users. JavaScript is often combined with HTML and CSS to build m...

Difficulty: 5/10

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Cockroach Labs interview details: 20 interview questions and 19 interview reviews posted anonymously by Cockroach Labs interview candidates.

People at Cockroach Labs Say

This information was sourced from reviews originally posted on Glassdoor.

Builds interesting complex systems without sacrificing quality

Solid pay, great work life balance

Making the switch to CRL was the best move I’ve ever made. No one here has a huge ego. The team also makes you feel like your voice is genuinely heard.

The work is challenging and engaging, and it gave me the opportunity to develop some valuable software engineering skills in a relatively short period of time. The engineering standards are high, especially due to the fact that the code base is open source and available for the general public to see.