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10 Best Problem Solving Interview Questions to Hire Top Engineer Talent

The market for hiring engineers is always competitive and is likely to continue to be so for at least the next decade. Top engineer talent is in high demand — which makes it all the more important to provide a great candidate experience during the hiring process.

The candidate experience can set your company apart from others in a highly competitive job market. For software engineers who go through multiple technical interviews at several companies — often simultaneously — the questions you ask matter. 

Many companies ask the same questions: tell us about a time you were challenged at work, for instance. For candidates, these kinds of questions can get stale. For employers, they can end up revealing relatively little about the engineer — other than how well they’ve memorized their answers.

Luckily, there’s a better option. Software engineering interview questions can be configured to provide candidates the opportunity to showcase something new. And, this can give hiring teams more information about a candidate’s approach to the software development life cycle, specific technical skills, and even their fit in the organization. 

In this article, we’ll take a look at the best problem solving interview questions to hire top engineer talent, and how this key step in the hiring process can improve the candidate experience and help recruit top software developers. 

What is a problem-solving interview?

A problem-solving interview is similar to a behavioral interview, in that it aims to understand how a candidate gathers data, analyzes a problem, and reaches a logical solution. Ideally, a problem-solving interview takes place outside the integrated development environment (IDE) to consider both technical skills and soft skills. 

In software engineering, this type of interview is both a technical interview and a way to assess a candidate’s knowledge in other areas. The hiring manager can use a skills assessment to test programming languages, present coding problems, and understand how much the candidate knows about the software development process. 

This interview should focus on higher-level questions. Craft your questions to gauge how well a potential new hire understands your company’s service, product, vision, and values. The software engineering interview should seek to understand problem-solving skills, thought process, and confidence in writing code, with a few questions targeting management experience, collaboration, and more.

Problem-solving interview vs. technical skills assessment

Software engineering interviews are often redundant with skill tests. It’s a problem that can easily frustrate candidates and detract from your candidate experience. Likewise, when a software engineering interview doesn’t lead to new information, hiring managers can have difficulty figuring out who is the best candidate. 

As a result, it’s best to use the problem-solving interview and coding challenge for different purposes. Use a technical skills assessment to: 

  • Test a programming language
  • Ask data structure-based questions
  • Set coding questions
  • See how much knowledge a software developer has of niche skills

Skills assessments are a crucial part of the screening process. Vervoe offers a library of assessments that can quickly provide insight into each candidate’s coding skills and more. Skill tests can be configured for specific roles, with pre-configured tests such as these .Net interview problem-solving questions or the C# Developer Skills Assessment Test

A problem-solving interview can be used after a candidate’s skills have been validated. In this step, you can talk to software engineers about emerging technologies, trends in the industry, their approach to problem-solving, and get them to speak more about their past experience at top tech companies. 

What are good problem-solving interview questions?

For recruiting teams seeking to hire at scale, we also offer a Problem Solving Skills Assessment Test. This assessment can provide insight into a candidate’s learning agility, problem-solving ability, and trainability. Candidate’s answers are scored using machine learning, so you get a list of ranked candidates with no one eliminated — faster and more efficient than manually sorting resumes or coding tests. 

Your interview questions should seek to dive deeper into the results of the technical assessment. Why did the software engineers answer the way they did? How did they approach the coding questions in which there were multiple possible solutions? 

Aim for better insight into the candidate’s knowledge, too. For top engineering talent, it’s not enough to simply write code. To go the distance with your company, it’s useful to have someone who can think creatively and put their problem-solving skills to work to adapt to your company culture and push innovative thinking. Here are some questions that can help you get to that deeper level of insight into a candidate’s abilities. 

10 problem-solving interview questions

These questions seek to connect past experiences and hypothetical scenarios in order to gauge problem-solving skills.

What are the pros and cons of the agile software development process?

The agile development process is highly touted in the software development world, but it doesn’t work at every company. This question aims to see if a software engineer can look at the agile software development process objectively and assess if the structure is working well for your unique team. 

Additionally, there are plenty of project management tools that a candidate can cite in their answer. The right candidate will be able to talk about how these tools enable this process to work smoothly while sticking to the main tenets of this approach to development. 

Can you give a brief explanation of your approach to testing and fixing bugs?

Testing is a crucial skill for a software engineer. Candidates should not only have the skills to perform bug testing but also have a specific approach to integrating testing throughout the software engineering process. Tests and assessments should be conducted throughout the software development life cycle, including after the app or website is launched. 

This question also aims to understand someone’s approach to problem-solving: can they find a bug, and fix it? A good answer would describe how the software engineer breaks down the app or website into components, prioritizing certain components that may be at higher risk, performing tests then recording and prioritizing defects, bugs, and other vulnerabilities. 

What are some tactics you would use to improve a website’s load time and performance?

This question is a good opportunity to see how the candidate combines technical knowledge with creativity and problem-solving. There are a number of ways to answer this question, including: 

  • Limiting HTTP requests
  • Utilizing CDNs and removing unused files/scripts
  • Optimizing files and compressing images
  • Browser caching and optimizing caches 
  • Applying CSS3 and HTML5

If you want to make this question even more interesting, provide a sample webpage and ask someone to critique it. Ideally, a candidate can walk you through their approach to optimizing the website, focusing on their process and teamwork in addition to their backend and design capabilities. 

How would you remove duplicate characters from a given array in Java?

This is a pretty technical question, one that works well in a coding interview or more technical job interview with a member of the engineering team. 

The correct answer recognizes that the problem in dealing with an array is not finding duplicate characters, but removing them. An array is a static, fixed-length data structure. 

You cannot change its length. As a result, the solution to deleting duplicate characters is to find duplicate characters using the first non-repeated character and create a new array, copying content into that array. 

If there are multiple duplicates, then the software engineer would need to come up with a strategy to minimize how many temporary arrays are created; copying content can put a burden on both memory and CPU. 

Do you contribute to open-source projects?

Many software engineers code in their free time, collaborating together to work on passion projects. It’s helpful to know if there’s anything the candidate is working on to hone their programming languages, learn a new skill, or contribute to the industry in another way. It can also help to hear another example of how they’re solving a real-world problem, rather than just serving a business need. 

Have you ever worked with a difficult client? What did you do?

It’s becoming more common for software engineers to interact directly with clients. Even if that isn’t the way your company is structured, engineers will have to explain their work to other stakeholders in the organization. 

Asking someone to talk about a challenging client or a project that didn’t go according to plan can help you understand how this person handles stress or works under pressure. This question seeks to understand someone’s people skills: how will they represent the company or the internal team? 

Watch out for any candidates that speak negatively about a brand or client. Regardless of what went wrong or who was at fault, the software engineer should keep comments limited to how they resolved the situation and used problem-solving skills. You don’t want to work with someone who might share something negative about your business down the line. 

How do you come up with time or cost estimates?

Software engineering teams often struggle to come up with timelines or budgets that are on the mark. If this position is one in which the software engineer will, or will eventually manage others, make sure they are thoughtful about the way they use company resources. 

Unlike a coding interview, this question aims to understand someone’s leadership potential, managerial experience, and other key soft skills that can help them be successful in the long run. 

How would you assess whether a new tool is worth investing in?

There are tons of platforms, software, and tools available to software engineering teams. It can be difficult to tell which ones are worth the investment. 

A software engineer can show their knowledge of the market, as well as an understanding of the problems that many teams need to solve, in their answer to this question. Ideally, the candidate will talk about issues or obstacles teams have faced in the past, and the way they evaluated different vendors to find a tool that kept the team productive. 

What technologies do you think will become outdated/more relevant in the next 10 years?

This is a fun way to connect with candidates, as it gives them a chance to share what they’re excited about in the industry. Whether someone talks about changes happening to their favorite programming language, tools they can’t wait to add to their tech stack, or something completely irrelevant, like blockchain, this gives them an opportunity to share their passion. 

What questions do you have for us?

Not every candidate will come prepared with their own questions, but those who do will show you how they’re thinking about the position already. Sometimes, the questions a candidate has about the company and the position can illuminate the things they’re most concerned with — whether remote work is an option, or how fast the company is growing, for instance. 

How to assess technical skills

If you’re looking for an easy way to take your next technical interview to the next level, consider using some of the skill assessments in Vervoe’s assessment library. Choose to make your own questions, or start with one of these templates:

Make sure someone has the right experience before you assess their potential as a top engineer at your company. 

Conclusion 

Software engineering jobs are well suited to problem-solving interviews. The interview questions you choose can show you more than a simple coding test. 

While coding questions reveal if someone completes a task, problem-solving interview questions reveal how someone approaches the task, and why they come to the solution they do. 

And, if your company is looking for software engineers who can think outside of the box, combining a technical interview and skills assessment gives you the best chance of finding those people.

Emily Heaslip

Emily Heaslip

Emily Heaslip is a versatile freelance copywriter who writes for finance, tech, and e-commerce brands. She currently lives in Cape Town and can be found running, hiking, and exploring the South African coast in her free time.

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