A Complete Guide on How to Best Be Prepared for Your Coding Interview
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- Coding interview questions usually focus on tech skills and soft skills.
- Be prepared to answer coding questions in real time during an interview.
- Some companies offer blogs and coding interview prep guides.
If you've landed an interview for a coding job, congratulations! You're in an industry with a strong job outlook.
The BLS also tracks job data for computer programmers. Although employment of people in this field is projected to decline 10% from 2021-2031, the BLS projects about 9,600 job openings annually.
Software Developer Projected Employment Growth
Source: Bureau of Labor Statistics
Computer Programmers Median Salary
Source: Bureau of Labor Statistics
Keep reading for our advice on how to prepare for coding interviews.
What Does a Coding Interview Generally Entail?
Interviews for a tech job often start with a casual phone call from the company's recruiter. Then, the applicant completes a technical interview, which can last about an hour and often occurs over Zoom, Microsoft Teams, or Google Hangouts. Before the coronavirus pandemic, some technical interviews happened in person and involved live white-boarding.
Applicants answer technical questions, and interviewers can watch them code in real time. Questions may focus on the applicant's ability to build or debug or prompt the applicant to show their knowledge of data structures and algorithms.
This is a chance to show off your coding skills and how you work with others. With the interviewer present, you can talk through your thought processes for completing the challenge, which allows you to demonstrate problem-solving skills.
While the interviewer evaluates how you complete the challenge, they also watch how attentive you are in checking and correcting code. The interviewer may assess your logical reasoning, use of best practices, and communication.
Along with coding challenges, the interviewer may ask applicants behavioral questions. These questions might cover your experience with various programming languages and development tools, what significant projects you've worked on, and what skills you'd bring to the position.
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What Concepts Are Emphasized During a Coding Interview?
Concepts frequently emphasized include arrays and strings, binary trees, dynamic programming, and linked lists. According to CoderPad, other common interview topics include breadth-first search algorithms, hash table use, and sorted lists of numbers. Interviewers may emphasize data structures and algorithms.
Common data structures tested include arrays, linked lists, stacks, and queues. Common algorithms tested include recursion, bubble sort, insertion sort, and binary search.
The interview topics also depend on the role you are interviewing for and the skills needed for the job.
How Will I Be Evaluated in a Coding Interview?
In a coding job interview, most tech companies focus on a handful of specific hard skills. Hard skills relate to hands-on experience, education, and training. These abilities include:
- Technical competency: Your ability to work quickly and accurately.
- Problem-solving: Your ability to identify issues and develop professional solutions.
- Testing: Your ability to self-correct code and fix errors before finalizing a project.
During a coding job interview, you may also need to perform coding tasks in real time. Industry leaders also say employers highly value candidates who specialize in one programming language.
Finally, tech companies are also well known for cultivating unique company cultures. So during a coding job interview, the interviewer may ask questions to gauge your soft skills. They may ask you to share how you work with teammates, what excites you about the industry, and how you manage your time at work.
What's the Best Way to Prepare for a Coding Interview?
Data structures and algorithms may make up the main part of coding challenges, so it's important to spend time on those topics when preparing for your interview. Try to mimic the actual interview conditions in your prep: Practice on a whiteboard and set a timer to emulate the time pressure during coding challenges. As you write your code, practice explaining your thought processes out loud.
It's also key to do your research on the company — this will give you a better idea of what languages, frameworks, and other tech it uses. You can also research the company's current strategies and goals to best identify and articulate how you will contribute to the company.
As the interview processes for many well-known companies are widely discussed, this research could lead you to specific information about your upcoming coding interview. At Google, for instance, applicants must pass a pre-screen and an onsite interview, which includes meeting with 4-6 Google employees for nearly an hour each.
Remember that while much of the interview will focus on technical skills, there will also be behavioral and soft skill components involved. It's a good idea to connect to the company's recruiter to get the full picture of the process.
Lastly, run through a couple of mock interviews. Have a friend play the role of the interviewer or use free mock interview sites like Pramp to practice.
What Are Some Common Coding Interview Questions I Should Expect?
Coding interview questions typically fall into two categories — behavioral and technical.
The goal of behavioral interview questions is to learn how you may think and respond to experiences and challenges in professional situations. Technical questions help the interviewer assess your job-specific skills.
Behavioral questions aren't exclusive to coding jobs. They're meant to highlight your ability to adapt, communication skills, conflict management skills, creativity, and goals. Here are examples of five questions that fit into this category:
Sample Behavioral Interview Questions
- Talk about a time when you had to explain a complex programming problem to someone who didn't understand technical jargon. How did you make sure the other person understood you?
- Describe a time when you were part of a project that failed. What happened, what did you learn from it, and how did it influence your approach to working on future projects?
- Describe a time that you disagreed with another programmer or member of your tech team. How did you resolve the conflict?
- Describe a project or initiative that you started on your own. What led you to do it?
- Give an example of how you reached an important goal. How did you do it?
After gauging your soft skills and how you might respond to interpersonal challenges, the interview may shift to your understanding of coding concepts and programming. Here are five questions you might include in your coding interview prep:
Sample Technical Interview Questions
- What is an array?
- What concepts are introduced in the object-oriented programming system?
- How can you reverse a string?
- What's the difference between Stack and Array?
- How do you determine if a string is a palindrome?
What Resources Should I Use to Prepare for a Coding Interview?
Cracking the Coding Interview, a book by software engineer Gayle Laakmann McDowell, breaks down 189 common technical interview questions and walks the reader through each solution. It also gives tips on how to complete on-the-spot algorithms and how to handle behavioral questions.
You can practice your coding skills on LeetCode, a website dedicated to helping tech professionals get jobs. It offers hundreds of test questions and even has a premier membership in which members can filter sample interview questions by specific companies.
Job and recruitment website Glassdoor is a repository for hundreds of sample interview questions that Glassdoor users were asked in their technical interviews.
Here's some additional interview prep advice from tech companies and industry experts:
- Meta, the parent company of Facebook and Instagram, says job candidates should be prepared to solve two coding problems during the initial job screening.
- Microsoft says its interviews may include demonstrating that you can write clean, bug-free code. Depending on the role sought, job-seekers may also need to demonstrate proficiency in algorithms, machine learning, or computer networking.
- LinkedIn, the career-focused social networking site owned by Microsoft, may ask coding job candidates to clone a directed graph or merge two sorted linked lists.
- Google uses 3-5 rounds of tech skill assessments in its interview process.
- Amazon evaluates your problem-solving skills and ability to create logical, maintainable code.
- Netflix interview questions focus heavily on design and subject matter expertise.
- Applicants can hone their soft skills and prepare for behavioral questions with Educative's Grokking the Behavioral Interview course.
How Long Should I Prepare for a Coding Interview?
Coding interview preparation time largely depends on the interviewee's experience level. If you're an entry-level programmer, it's a good idea to spend at least 12 weeks preparing. If you have more experience, 4-8 weeks is suggested for interview prep.
Study the company's programming language and tools of choice. Practice a couple of coding challenges each day — don't let your practice be a cram session right before your coding interview. Finally, as you practice, make sure to time yourself to see how you are progressing.
Frequently Asked Questions About Coding Interviews
How long are coding interviews?
The phone screen portion of the coding interview typically lasts up to one hour. The second, more technical part of the interview can take many hours. The onsite or final round interview can take the whole day.
Where can I practice coding?
There are many ways to practice coding and prepare for your coding interview. LeetCode provides practice opportunities in more than 14 languages and more than 1,500 sample problems. Applicants can also practice their coding skills and interview prep with HackerRank.
How do I know if my coding interview went well?
There are a variety of indicators that your coding interview went well. These may include going over the allotted time, being introduced to additional team members, and receiving a quick response to your thank you email.