How To Ace The Coding Interview: Strategies and Resources
Acing the coding interview means passing an interview called “the coding interview”. There are many aliases for the coding interview such as “the technical interview” and “the software engineering interview”, but they all test a candidate’s abilities in critical thinking, programming, data structures, algorithms, and communication. A coding interview is one of the 8 main types of coding interviews.
In this article, we will provide you with a practical guide for preparing and passing the coding interview portion of a technical interview loop at large companies (like Google, Meta, Amazon, and Apple), tech unicorns (like ByteDance, Stripe, and Plaid), and other Fortune 500 companies (like Walmart Labs, Capital One, and AT&T).
We will guide you through the coding interview preparation process by teaching you strategies such as learning a single programming language like Python, reviewing the fundamentals of computer science (i.e., data structures and algorithms), familiarizing yourself with the interview process, practicing the most relevant coding interview questions (based on the most important data structures and algorithms), and maintaining an interview preparation schedule.
We will also discuss other strategies to allow you to demonstrate your communication skills and give you paid and free resources like the websites you need to practice mock coding interviews (like Pramp and Interviewing.io), the books you should read to prepare for technical interviews (like Cracking the Coding Interview), and the coding interview-related courses that are worth taking (like AlgoExpert).
At the end of this article, we will discuss the difficulty and amount of effort that is necessary to crack coding interviews for companies like Google and Amazon.
1. Master A Single Programming Language
Mastering a single programming language means becoming proficient in a popular programming language like Python, Java, C++, or JavaScript to the point where you’re able to comfortably solve coding interview problems that revolve around common data structures and algorithms.
This is important because you don’t want to divide your focus on learning multiple programming languages which results in shallow knowledge of multiple languages because coding interview interviewers are assessing you on the depth of your programming language knowledge.
Appropriate programming languages that you can use for a coding interview are listed below.
- Python
- Java
- C++
- JavaScript
- C
- Kotlin
- Swift
The percentage of developers that use these programming languages is shown in the image below. The data is from the StackOverflow 2023 developer survey which covers 2022 developer data.
Depending on the company, you may be able to use other languages outside the aforementioned common programming languages for technical interviews. However, if you don’t use a popular programming language then you won’t be able to find solutions to practice coding interview problems and it could be hard matching you with interviewers at companies, reducing your chances of getting interviews.
To master a programming language, you’ll need to practice using the programming language on questions that are similar to what would be asked in a coding interview. Many people learn to use LeetCode as a part of their interview preparation process because of the high quality and interview-relevant questions that LeetCode has on its platform. LeetCode also accepts all popular programming languages on its platform for you to master and practice a programming language.
Is There A Best Programming Language For Coding Interviews?
There is not a single “best” programming language for coding interviews. However, Python is considered the best language for coding interviews amongst interviewees because of its readability, versatility, and productivity.
By using the Python programming language during technical interviews, you’ll be able to program solutions to problems in fewer lines of code compared to other programming languages like Java, JavaScript, and C++.
Should You Learn A Different Programming Language For Coding Interviews?
You should not learn a different programming language for coding interviews if you’re already familiar with a popular programming language that is acceptable for a coding interview. Learning a new programming language for the purposes of coding interviews is unproductive in this case because you can instead focus on mastering data structure and algorithm-type questions.
An exception to this rule is if you’re interviewing at a company like Jane Street for a software engineering role that requires a specific programming language like C++ on the job. In this case, you’d need to learn C++ for the purposes of their coding interview if you don’t already know it.
2. Review The Fundamentals Of Computer Science
Reviewing the fundamentals of computer science means solidifying your understanding of computers in terms of computation (like bytes, bits, variables, and programming), data structures (like lists, stacks, and queues), and algorithms (like bubble sort, heap sort, and depth-first search) on a software-level.
Your knowledge in computation and programming is tested by your ability to articulate solutions to coding interview problems and map theoretical solutions into working code implementations.
Data structures represent how information is organized and stored as data in computers, and algorithms are a set of predetermined rules or steps to accomplish specific tasks. Both of these topics are thoroughly tested together in a technical interview with your understanding of time and space complexity (otherwise known as Big-O notation).
The table below depicts the worst-case time complexities for common operations on the most common data structures that are used in coding interviews.
| Data Structure | Get | Put | Replace | Remove |
| Array (unsorted) | O(n) | O(1) | O(1) | O(n) |
| Array (sorted) | O(log n) | O(n) | O(1) | O(n) |
| Linked List | O(n) | O(1) | O(1) | O(n) |
| Doubly Linked List | O(n) | O(1) | O(1) | O(1) |
| Stack | O(1) | O(1) | O(1) | O(1) |
| Queue | O(1) | O(1) | O(1) | O(1) |
| Hash Table | O(n) | O(n) | O(n) | O(n) |
| Binary Search Tree | O(n) | O(n) | O(n) | O(n) |
| AVL Tree | O(log n) | O(log n) | O(log n) | O(log n) |
| Heap (Binary Heap) | O(1) or O(log n)* | O(log n) | O(log n) | O(log n) |
These fundamentals of computer science are significantly evaluated during a technical interview because this knowledge is the basis of the role of a software engineer, and that’s why the fundamentals of computer science are important to review to pass a coding interview.
What Are The Most Important Data Structures To Study For Coding Interviews?
There are 9 most important data structures to study for coding interviews which include strings, arrays, hash tables, stacks, queues, linked lists, trees, heaps, and graphs.
Studying each of these data structures, understanding their use cases, and knowing how and when to apply them will improve your chances of passing the vast majority of coding interviews. These data structures are the 9 most important data structures to study for a coding interview because they’re the most common data structures that are used in optimal solutions for coding interview problems.
What Are The Most Important Algorithms To Study For Coding Interviews?
The most important algorithms to study for a coding interview are insertion sort, depth-first search (DFS), breadth-first search (BFS), and binary search.
Many coding interview problems have optimal solutions related to these most important algorithms. However, to significantly improve your chances of passing coding interviews, you’ll want to study all 6 types of essential algorithms.
The 6 types of algorithms you should study for a technical interview include sort algorithms, searching algorithms, recursive algorithms, divide-and-conquer algorithms, tree traversal algorithms, graph algorithms, and sliding window algorithms.
3. Familiarize Yourself With The Structure Of A Coding Interview
Familiarizing yourself with the structure of a coding interview means understanding the structure and format of a coding interview. This allows you better to manage your time studying and time during an interview, allowing you to become more comfortable with interviewing to pass a coding interview.
The most common structure for a coding interview is synchronous, conducted either in-person or remotely through webcam and audio (i.e. Zoom or Google Meet), and with one interviewer. The other main types of coding interview structures are listed below.
- Assessment Type: Coding interviews can be either asynchronous or synchronous. Asynchronous assessments (projects or assignments) are given to you to complete on your own time with a specific due date (i.e. coding challenges on sites like HackRank), and synchronous assessments are conducted in front of an interviewer.
- Format: Coding interviews can be conducted remotely or in person.
- Number Of Interviewers: Coding interviews can be conducted with zero, one, or multiple interviewers
- Technical assessments without an interviewer are for asynchronous assignments where you’re evaluated by test cases and a computer.
- Having one interviewer is common for phone interviews or on-site interviews where you’re evaluated in real-time.
- Having multiple interviewers is called a panel interview. In the context of software engineer coding interviews, a panel interview means that you have multiple members of a company interviewing you at the same time.
What Is The Typical Schedule Of A Coding Interview?
The typical schedule of a coding interview is about 5 minutes of introduction, approximately 30 to 45 minutes of coding, and about 5 minutes to ask questions to your interviewer. It’s important to understand this to help better you manage your time during the coding portion of the technical interview.
An example timeline of a coding interview is shown in the image below.
Knowing this, you should aim to solve coding interview questions in about 25 to 35 minutes while practicing for coding interviews without the pressure of a real interview.
4. Practice Coding Interview Questions
Practicing coding interview questions means actively working through practice coding interview problems that are similar to the questions that are asked during a coding interview. This involves solving a technical problem by programming, practicing organizing your thoughts and approaches, and memorizing common solution patterns that appear within coding interview problems.
Practicing coding interview questions enables you to be prepared for the technical questions that are asked during real coding interviews. Often, coding interviewers ask coding interview questions that are directly on sites like LeetCode or variations of the questions. This is why it’s important to practice solving coding interview questions ahead of time and learn how to solve coding interview questions to pass a coding interview.
However, there are thousands of practice programming questions for coding interviews spread across multiple coding interview platforms. You should prioritize practicing the most important coding interview questions like array-related and sorting-related problems because they’re more relevant to passing coding interviews.
What Are The Most Important Coding Interview Questions To Practice?
The most important coding interview questions to practice are questions related to data structures (like arrays, linked lists, and trees) and algorithms (like sorting and traversing). These coding interview questions are important to practice because they’re the most commonly asked types of technical interview questions.
Coding interview questions that are related to these topics are also the foundational questions that more advanced and harder coding interview questions build upon, so it’s important to understand and know how to solve these coding interview questions.
Where Do You Practice Coding Interview Questions?
You practice coding interview questions on websites like LeetCode, HackerRank, and CodeSignal. Each of these platforms offers a wide variety of practice problems for technical interviews that cover an array of topics related to the exact data structure and algorithm questions asked during real coding interviews.
Each of the questions is also sorted further into difficulty tiers of easy, medium, and hard, so you can incrementally improve your ability to solve coding problems as a beginner.
5. Practice Demonstrating Your Communication Skills
“Practice demonstrating your communication skills” means deliberately practicing your ability to articulate your ability to think, solve coding problems, and debug issues to another person, within a coding interview setting. This includes skills such as articulating your thought process to determine possible solutions to a problem, implementing the code to a solution, and verifying whether your solution is optimal.
Demonstrating your communication skills is important to pass a technical interview because your interviewer will be able to get a better evaluation of your skills as a candidate compared to just reading the code you write.
How Should You Communicate During A Coding Interview?
You should communicate during a coding interview in a way that allows your interviewer to acquire enough positive signals about your programming skills, critical thinking skills, and communication skills. Remember that your interviewer can only evaluate you based on your code and what you’re communicating with them.
You should not make any assumptions that aren’t explicitly clear between you and your interviewer during a coding interview.
An example of what you should do includes explaining to your interviewer the pros and cons of different approaches to a problem, rather than just stating there are multiple solutions. Another example of what you should do is make sure that you communicate to your interviewer any optimizations you’re writing in your code, so your interviewer understands your thought process behind what’s going on.
By practicing how to communicate, you increase your chances of passing the coding interview. This is why it’s important to understand how to communicate during a coding interview, so you can practice these skills before an actual technical interview.
How Do You Practice Communication For A Coding Interview?
You should practice communication for an interview by vocalizing your thought process while you’re practicing technical interview problems as if you had an interviewer in front of you if you’re studying by yourself. Otherwise, you can practice communication by doing mock software engineer coding interviews.
6. Maintain An Interview Preparation Schedule
To “maintain an interview preparation schedule” means to make sure that you have a structured approach you follow to prepare for a coding interview. Effective interview preparation schedules vary by individuals based on their existing knowledge and experience, but they generally follow the same types of schedule schemes.
If you want to pass the coding interview, at a minimum, you should be preparing for at least an hour every day weekday leading up to your real coding interviews. If possible, you’ll want to practice interview questions and related material for coding interviews for multiple hours over the weekend.
Fundamentally, you want to become comfortable with solving every type of common coding interview question that can be asked, so your interview schedule’s intensity should reflect that against the timeline you have until you have your technical interviews.
Can You Prepare For A Coding Interview In 3 Months?
Yes. You can prepare for a coding interview in 3 months. This is realistic for college students and bootcamp graduates who have a strong foundation in programming, data structures, and algorithms.
Studying coding interview-specific material, practicing coding interview questions, and doing mock interviews over a duration of 3 months is enough to crack interviews for FAANG companies like Google, Amazon, Apple, and Google.
Can You Prepare For A Coding Interview In 1 Month?
Yes. You can prepare for a coding interview in 1 month. However, this will be rigorous and time-intensive if you are a college student or bootcamp graduate, even if you have a strong foundation in programming, data structures, and algorithms.
Studying coding interview-specific material, practicing coding interview questions, and doing mock interviews over a duration of 1 month will require you to prepare for approximately 4 to 8 hours per day to crack interviews for FAANG companies like Google, Amazon, Apple, and Google.
Can You Prepare For A Coding Interview In 1 Week?
No. You cannot prepare for a coding interview in 1 week. It’s highly unlikely that you will pass a coding interview if you give yourself a single week’s time of preparation.
How Many Hours Should You Study Per Day?
You should study approximately 2 to 4 hours per day if you’re new to coding interviews, 1 to 3 hours per day if you’re familiar with coding interviews, or 1 to 2 hours per day if you’re experienced with coding interviews if you have your coding interviews within 1 to 3 months.
The exact amount of time you should be studying depends on a variety of criteria such as your current skills in data structures and algorithms, time availability, stamina in studying, and ability to focus on studying.
7. Practice Coding Interviews Through Mock Interviews
Practicing coding interviews through mock interviews means using mock interviews as a method for practicing for technical interviews. Mock interviews (also called “mock coding interviews”) are simulations of real coding interviews where two people (as an interviewer and interviewee) are paired together with a mock coding interview problem to solve and work through.
Practicing coding interviews through mock interviews is important in interview preparation to pass a coding interview because it helps you get more comfortable with an environment that’s significantly more similar to a real coding interview. You’ll be presented with a question you didn’t pick, and you’ll be expected to solve it as if it’s a real interview, not allowing you to think to yourself or use outside sources for hints or tips.
You can either pay for mock interviews with professional experience as interviewers at tech companies like Google, Meta, and Amazon, or you can do mock interviews for free through some of the best mock coding interview platforms like Pramp (where you’ll trade off with a partner to be both an interviewer and interviewee).
What Are The Best Mock Coding Interview Platforms?
The best mock interview platforms include mock interview platforms like Pramp, Interviewing.io, and Meetapro. Pramp is a free mock interview coding platform, and both Interviewing.io and Meetapro are paid platforms that match you with industry experts for mock interviews.
How Often Should You Do Mock Coding Interviews?
You should do mock coding interviews as frequently as you reasonably can leading up to the dates of your real coding interviews. The more exposure you have to mock coding interview settings, the more comfortable you will be with real coding interview settings. This increases your chances of passing coding interviews.
8. Review Books About The Coding Interview
Review books about the coding interview means learning about passing the coding interview through reading popular coding interview-related books like Cracking the Coding Interview by Gayle Laakmann McDowell and Elements of the Programming Interview by Adnan Aziz, Tsung-Hsien Lee, and Amit Prakash.
Reviewing and reading the best books for coding interview preparation provides you with a structured approach to learning about what technical interviews entail and how to approach various types of coding interview problems compared to solving random questions on platforms like LeetCode.
Is Cracking The Coding Interview Still A Good Book In 2023?
Yes. Cracking the Coding Interview is still a good book in 2023 to read and learn about software engineer coding interviews.
While the difficulty of real coding interview questions in 2023 is more difficult than the questions that are asked within the book today (which wasn’t the case at the time the book was initially written), the book still provides the reader with a solid primer into what to expect during a coding interview and how to reason through passing a coding interview.
9. Review Courses About The Coding Interview
Reviewing courses about the coding interview means learning about the components of the coding interview (i.e., data structures and algorithms) and/or the coding interview itself through online courses. Online courses like AlgoExpert and InterviewCake provide a combination of video lectures, practice problems, and solutions toward aspects of the coding interview to help you pass the coding interview.
Reviewing and reading the best courses for coding interview preparation provides you with a structured approach to learning about the components of a technical interview and how to approach various types of coding interview problems compared to solving random questions on platforms like LeetCode.
What Are The Best Free Courses For Coding Interview Preparation?
The best free courses for coding interview preparation include Coursera’s Algorithms Specialization by Stanford University and MIT OpenCourseWare’s Introduction to Algorithms for learning about data structures and algorithms to pass coding interviews.
How Much Effort Is It To Study For Coding Interviews?
Studying for coding interviews requires a significant amount of effort if you’re not proficient in programming, data structures, and algorithms. The exact amount of studying for coding interviews depends on the company you’re interviewing for.
For instance, if you want to pass the Google coding interview it will require more effort than passing a coding interview for Capital One. This is because of the different levels of software engineering competencies that are tested for.
How Do You Prepare For The Google Coding Interview?
To prepare for the Google coding interview, you should master the intuition and application of advanced topics in programming, data structures, and algorithms in addition to the fundamentals. This includes topics in data structures such as self-balancing trees and advanced topics in graph theory like topological sorting.
Is The Google Coding Interview Difficult?
Yes, the Google coding interview is considered extremely difficult in comparison to coding interviews for other similar-tier and prestige companies like Amazon and Meta. To pass Google’s coding interviews, you’ll need to be comfortable with solving advanced data structure and algorithm questions that involve less-common algorithms like A* pathfinding and Djistra’s algorithm.
How Do You Prepare For The Amazon Coding Interview?
To prepare for the Amazon coding interview, you should prepare the same as you would prepare for any other technical interview by learning and mastering the fundamentals of programming, data structures, and algorithms.
Is The Amazon Coding Interview Difficult?
Yes, the Amazon coding interview is considered difficult in comparison to coding interviews for other companies like Capital One, Expedia, and Vanguard.
