Fastly Interview Questions

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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

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

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

Text Justification

Can you justify input text represented by an array of words so it looks pretty when printed and the whitespaces are balanced? For example, in the above image, we have an input array of "wow", "so", "cool", "is", "algodaily!" . This is a list of words we need to properly arrange, with the ideal ...

Difficulty: 9/10

Nth Smallest Number in a Stream

Many modern programming languages have the notion of a stream. A stream is a resource _that's broken down_ and sent usually over a network in small chunks. Imagine a video that's playing it would be inefficient to need to download an entire 1 gigabyte movie before being able to watch it. Inste...

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

Missing Number In Unsorted

Assume we're given an unsorted array of numbers such as this: 2, 5, 1, 4, 9, 6, 3, 7 We are told that when this array is sorted, there is a series of n consecutive numbers. You are given a lower bound and an upper bound for this sequence. There is one consecutive number missing, and ...

Difficulty: 4/10

Max Rectangle in a Histogram

We're given a histogram like the following, where contiguous sharing a common border or touching bars are made up of different heights. Let's assume all bars have the same width. The histogram is converted to an array of the heights of the bars: js const histArr 3, 1, 4, 2, 2, 1 ...

Difficulty: 8/10

Length of String Compression

Let's define the "compacting" of a string as taking an input like the following: 'sstttrrrr' . We want to take the number of sequential appearances number of times it shows up in a row of each letter: s: 2 t: 3 r: 4 And denote them next to the original character in the string,...

Difficulty: 6/10

Introduction to React

Introduction to React React is a popular JavaScript library for building user interfaces. It was developed by Facebook and is widely used in frontend development. React follows a component based architecture, where each UI element is represented as a reusable component. This makes it easier to...

Difficulty: 5/10

Recursive Backtracking For Combinatorial, Path Finding, and Sudoku Solver Algorithms

Recursive Backtracking For Combinatorial, Path Finding, and Sudoku Solver Backtracking Made Simple Backtracking is a very important concept in computer science and is used in many applications. Generally, we use it when all possible solutions of a problem need to be explored. It is also ...

Difficulty: 5/10

Anomaly Detection In Machine Learning

**Anomaly Detection** **What is an Anomaly** An Anomaly https: www.collinsdictionary.com dictionary english anomaly defined as: *Something that is different from what is usual or expected.* Detecting anomalies has many useful applications. For example anomaly detection enables us to det...

Difficulty: 5/10

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