AT&T Interview Questions

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

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

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

Find First Non-Repeating Character

You're given a string of random alphanumerical characters with a length between 0 and 1000 . Write a method to return the first character in the string that does not repeat itself later on. So if we had a string input of "asdfsdafdasfjdfsafnnunl'" , we can see there are multiple letters that...

Difficulty: 4/10

Merge Two Binary Trees

Merging Two Binary Trees The Problem Statement You are presented with two binary trees. Your task is to merge these trees into a single, new binary tree. ! Merging Binary Trees https: storage.googleapis.com algodailyrandomassets curriculum trees merge two binary trees cover image.png ...

Difficulty: 5/10

Merge Intervals

This is a classic interview question that is used in _a lot_ in technical interviews, frequently in the form of a calendar or meeting management application. As such, we'll also assume the same use case, as it's easier to visualize. Suppose we're given a few arrays, like 1, 4 , 2, 5 , 7,...

Difficulty: 5/10

String Breakdown

We're given a string and need to see if it can be broken down into words from a dictionary array. For example: js const str "applecomputer" const dictArr "apple", "computer" stringBreakdown str, dictArr true Assuming that there are no repeats in the dictionary array, ca...

Difficulty: 7/10

Least Missing Positive Number

We have an unsorted array of integers such as the following: 0, 3, 1, 2, 1 csharp if len 2 return Math.Max nums 0 , nums 1 In the above example, the minimum number is 2 and the maximum is 3 . If it were sorted, it would look like: 2, 1, 0, 1, 3 csharp ...

Difficulty: 4/10

Word Search Solver

Introduction to Word Search In this section, we will provide an overview of the word search problem and discuss its applications. The word search problem involves finding a specific word within a grid of letters. The grid can be of any size and the word can be horizontal, vertical, or diagonal...

Difficulty: 5/10

How to Get Better at Approaching Coding Interviews

So you want to get better at interviewing? It's all in the approach this guide is a **step by step walkthrough** on exactly how to answer coding interview question from companies like Facebook, Amazon, Microsoft, Netflix, or Google. This article will cover a lot. It'll walk you through a com...

Difficulty: 5/10

Understanding the Data: Statistics

Introduction In this lesson, we will get started with some very basic statistical analysis. A statistic of data is just a summary of that data for humans and computers. Imagine you have a medical history of 2 million people from multiple hospitals, and you want to know which disease is worst ...

Difficulty: 5/10

Metrics: Latency, CPU, Memory, Error Rates

What are metrics and why do they matter? Generally speaking, _metrics_ are simply quantitative measures used for comparing, tracking, and understanding the performance of a specific process. They are highly beneficial because they help us evaluate our progress and overall efficiency, or simply p...

Difficulty: 5/10

Is Software Engineering a Winner Takes All or Auction Profession?

Cal Newport has studied the science of high mental performance for years. He's written multiples books about getting better results in school and work, and has recently shifted his attention towards the problems of the modern day technology worker. Newport himself is an Associate Professor of Co...

Difficulty: 5/10