Ability to solve typical problems in interviews
The art of live coding in JavaScript is becoming increasingly important to a successful career as a web developer. If you’re looking to excel in interviews and showcase your skills in real time, then this article is for you. I invite you to delve into the world of typical interview tasks in the live-coding section, where you can showcase your knowledge of JavaScript. In this article, we will look at popular tasks, approaches to solving them, and give useful tips to help you cope with this challenge. Let’s start diving into the world of JavaScript and prepare for successful job interviews!
1. Introduction
Importance of live-coding tasks in job interviews
The developer hiring process often uses live coding, or live coding, to assess a candidate’s skills in real time. This is a popular format that allows you to test the practical application of the candidate’s knowledge and skills in the context of real problems or abstractions.
Live-coding tasks in JavaScript are an essential component of many technical interviews. They measure a candidate’s ability to understand basic language concepts, apply an algorithmic approach to problem solving, and evaluate debugging and code testing skills.
Purpose and structure of the article
The purpose of this article is to provide an overview of the most common tasks that can be encountered in live coding interviews and are related to JavaScript. We will consider various categories of problems, as well as approaches to solving them.
2. JavaScript basics for job interviews
To successfully complete live-coding tasks in an interview, you need to have a good understanding of the basics of JavaScript. In this section, we will cover a few key topics that you should familiarize yourself with before the interview.
Variables, data types and operators:
Variables are the main tool for working with data in JavaScript. You should review the different ways of declaring variables and understand the difference.
Explore the different data types that JavaScript supports, such as numbers, strings, booleans, and more.
Operators allow you to perform operations on data, including arithmetic, logical, and comparative operations.
Conditional statements and loops:
Conditional statements (if-else, switch) allow you to control the flow of program execution depending on the conditions.
Loops (for, while) allow you to repeat certain pieces of code, which is often useful when processing arrays and other collections.
Functions and scope:
Functions are the basic building block in JavaScript. You need to have a good understanding of how to declare functions, pass arguments, and return values.
Particular attention should be paid to the concepts of recursion, closure, function execution context, and variable scope.
Also look at higher-order functions that can take or return other functions.
Arrays and objects:
Arrays and objects are the basic data structures in JavaScript. You must be able to create, manipulate and perform operations on them.
Learn different methods for working with arrays, such as adding, removing, searching for elements, and other manipulations.
Familiarize yourself with the basic principles of working with objects, including accessing their properties and methods.
3. Preparing for an interview
To successfully complete live-coding tasks in an interview, thorough preparation is necessary. In this section, we’ll go over a few important steps to help you prepare for your interview.
Exploring Popular Algorithmic Problems
There are many resources where you can find popular algorithmic problems that are often found in job interviews. Some of these resources include “Cracking the Coding Interview” and various online platforms for preparing for technical interviews. Familiarization with these problems and practice solving them will help you become familiar with typical approaches to solving and improve your skills. I also advise you to start your journey in learning problems on leetcode to become a real guru of algorithmic problems.
Useful materials:
– Roadmap for the study of algorithmic problems: link
An example solution is here in python, but it shouldn’t be hard for you to translate the solutions into javascript. The main thing is to understand the pattern itself and the solution algorithm.
– And here is a turnip with the solution of the same problems in Javascript) link
Practice of live-coding tasks
Real practice is the key to success. Try to solve many live-coding tasks yourself. This will help you master various algorithms, data structures and problem solving techniques. It is also recommended to conduct live-coding practice sessions with other developers or use online platforms that offer their own practice tasks and code editors.
4. Typical tasks for interviews
Interviews often ask typical tasks that allow you to evaluate the skills of a developer in real time. In this section, we’ll look at a few examples of such JavaScript-related tasks. I will give an answer to each problem, but you need to try to solve them yourself in order to understand the logic of the solution.
Tasks for working with arrays
Find the largest and smallest element in an array without using Math.max and Math.min.
Process data in array in a certain way with O(n) solution.
// Необходимо обработать массив таким образом, чтобы распределить людей по группам городов // Данные на вход const people = [ { name: 'Alex', city: 'Moscow', }, { name: 'Ivan', city: 'Moscow', }, { name: 'Joe', city: 'New York' }, { name: 'Johan', city: 'Berlin' }, ] const groupByCity = (array) => {} // Данные на выход /* { 'Moscow': [ 'Alex', 'Ivan' ], 'New York': 'Joe', 'Berlin': 'Johan' } */Combining intervals in an array
const array1 = [[1, 3], [2, 6], [8, 10], [15, 18]]; // [[1, 6], [8, 10], [15, 18]] const array2 = [[1, 4], [4, 5]];' // [[1, 5]] const array3 = [[11, 12], [2, 3], [5, 7], [1, 4], [8, 10], [6, 8]]; // [[1, 4], [5, 10], [11, 12]] function merge(intervals) { // ваш код } console.log(merge(array1)); console.log(merge(array2)); console.log(merge(array3));
Tasks for working with objects
Object transformation
// Объект на вход const object = { a: { d: { h: 4 }, e: 2 }, b: 1, c: { f: { g: 3, k: {} } } }; const addLevels = (obj) => {} // Данные на выход /* updatedObject { a: { d: { h: 4, level: 2 }, e: 2, level: 1 }, b: 1, c: { f: { g: 3, k: [Object], level: 2 }, level: 1 }, level: 0 }*/ // Object { a: { d: { h: 4 }, e: 2 }, b: 1, c: { f: { g: 3, k: {} } } }Task #2
/* Задача: Напишите функцию flattenObject(obj), которая принимает в качестве аргумента вложенный объект obj и возвращает новый объект, в котором все свойства объекта obj "разглажены" (преобразованы в одноуровневую структуру), с использованием точечной нотации для представления иерархии свойств. */ const obj = { a: { b: { c: 1, d: 2 }, e: 3 }, f: 4 }; const flattenObject = (obj) => {} const flattenedObj = flattenObject(obj); console.log(flattenedObj); // Ожидаемый результат: { 'a.b.c': 1, 'a.b.d': 2, 'a.e': 3, 'f': 4 } || { "f": 4, "a.e": 3, "a.b.c": 1, "a.b.d": 2 }
Tasks for working with strings
Check if the given string is a palindrome. Now it is popular to complicate this task. Let’s add a condition that will ignore spaces, punctuation marks, etc. We will also ignore case.
/* Примеры: - Казак // true - Madam, I'm Adam // true - А в Енисее - синева // true - О, духи, от уборки микробу-то и худо // true - Не палиндром // false */Check if 2 given strings are anagrams
const anagram = (strA, strB) => {} console.log(anagram('finder', 'Friend')) // true console.log(anagram('hello', 'bye')) // falseConvert a string to an object, separating properties on a dot.
const str="one.two.three.four.five"; // RESULT /* { one: { two: { three: { four: { five: } } } } } } */
Problems for working with numbers
Check if the given number is prime.
Calculate the factorial of the given number.
Find the sum of all numbers in the given range.
Tasks for working with recursion
Implement a recursive function to calculate Fibonacci numbers.
function fibonacci(n) {} // ? memo console.log(fibonacci(8)); // 21Expand nested arrays using recursion.
function flattenArray(arr) {} const nestedArray = [1, [2, [3, 4], 5], 6]; console.log(flattenArray(nestedArray)); // [1, 2, 3, 4, 5, 6]
Tasks for knowledge of basic functions and methods of Javascript
Implement your own map, filter, reduce methods. It is necessary to preserve all the features that native methods have: calling through a dot, getting all the necessary arguments
Write your own debounce and throttle functions
Write a sleep function that stops code execution for a certain amount of time.
console.log('Начало'); await sleep(2000); // Приостанавливаем выполнение на 2 секунды console.log('Прошло 2 секунды');
5. Approaches to problem solving
When solving live-coding tasks in interviews, there are several approaches that can help you solve the task effectively. In this section, we will look at some of them.
Iterative approach
The iterative approach is based on the use of cycles and sequential operations on data. This approach is suitable for tasks that require iterating arrays, performing repetitive operations, or changing the state of objects. It is easy to implement and understand.
Recursive approach
The recursive approach is based on calling the function itself. It is widely used when dealing with tree data structures, graphs, or tasks that can be broken down into smaller subtasks. Recursion can be an elegant solution, but requires attention to the base case and stop condition to avoid looping.
Using built-in methods and functions
JavaScript offers many built-in methods and functions that make it easy to work with arrays, strings, objects, and other data structures. Using these methods can significantly reduce the amount of code and increase its readability. Some of these methods include
forEach,map,filter,reduce,sortand others.Decision optimization
When solving problems, it is important to pay attention to the optimization of solutions. This may include choosing the most efficient algorithm, reducing the complexity of the algorithm, using appropriate data structures, and so on. Decision optimization helps improve code performance and efficiency.
6. Tips for performing live-coding tasks
Performing live coding tasks in job interviews can be a challenge, but with the right preparation and some tips, you can improve your chances of successfully completing the task. In this section, we will look at some useful tips.
Understand the requirements of the task
Before you start coding, make sure you fully understand the requirements of the task. Read the problem statement carefully and define its input and output data. Clarify any ambiguities with the interviewer to make sure you understand the task correctly.
Break the task into subtasks
If a task seems daunting, try breaking it down into smaller subtasks. This will help simplify the solution and make it more maintainable. Looking at the task step by step will allow you to better organize your thoughts and understand what steps you need to take to achieve the goal.
Test your solution
Validating and testing your solution are important steps. Test your solution against various inputs, including edge cases. Make sure the code works correctly and returns the expected results. This will help you detect and correct possible errors.
Write clean and readable code
The approach you use when writing code should be clear and easy to read. Use clear and descriptive variable and function names. Divide code into logical blocks using indentation and formatting. Add comments to explain complex or non-trivial parts of the code.
Be sociable
Don’t forget that live-coding interview tasks are not only a technical test, but also a test of your communication skills. Explain your thoughts and reasoning aloud so that the interviewer understands your decision logic. If you’re stuck or need help, don’t hesitate to ask for advice.
Conclusion
In this article, we looked at typical tasks at interviews in the live-coding section and how to prepare for their implementation. We also discussed approaches to problem solving, tips for getting things done, and the importance of communication during an interview.
Remember that successfully completing live-coding tasks takes practice, perseverance, and confidence. The more practice you get, the more confident you will be in interviews. We wish you good luck in your preparations and successful results in your future interviews!
PS If you have the best solutions to the problems presented, leave comments!
