Are code interview challenges a good strategy to find the best developers for your project?
Finding the best developers is often a challenge. Having a person with the right qualifications is sometimes enough. But, for certain jobs, having the right work mindset is far more important.
Code interview challenges are a great tool used by the people responsible for hiring for a company to test out their candidate’s knowledge and problem-solving in one single sweep.
In this article, we’ll explore what coding challenges are; what you should consider when creating a coding challenge for interviews; and provide you with some sample questions to get you started. Let’s begin!
What are Code Interview Challenges?
Coding challenges are usually employed during hiring processes to assess candidates and help recruiters pick the candidates better suited for the job. They are essentially programming tests for hiring developers.
These types of code interview challenges will usually test the candidate’s knowledge and problem-solving skills. For example, using questions that will force them to come up with efficient or out-of-the-box solutions for relatively common issues they may face in their day-to-day work.
Different Types of Coding Challenges
Coding challenges can take many forms, depending on the type of developer a company is looking for.
Let’s have a look at the most common types:
- Take-home: The employer will send the candidate the test and allow them to solve it on their own time with a pre-established deadline. This is a good test to hand out if your candidate mostly works by themselves since you can evaluate how they would do if given a problem and told to solve it on the job.
- Pair-Programming: As the name suggests, this coding challenge interview is done with a team of two. The interviewer and the candidate will try to solve a problem together, bouncing off each other. This test is good for evaluating how your candidate relates to their peers and their communication skills. However, it may be a non-ideal solution to test their problem-solving skills since it puts the candidate on the spot.
- Whiteboarding: In this type of in-person coding challenge, the candidate is given a problem to solve and asked to do so on a whiteboard or canvas in front of the interviewer and/or the rest of the dev team, with little to no input from them. Much like pair-programming challenges, these put the candidate on the spot and can lead to bad interviews due to nerves.
- Screening Questions: A coding challenge that is more akin to a quiz. This method is usually very poor when evaluating a particular person’s methods and problem-solving skills since you’ll only see their final answer. But it’s a good method to assess a large number of candidates in a short amount of time.
What Are The Best Practices For Code Interview Challenges?
Code interview challenges can be great tools to give your candidate developer a problem and see how they process and try to find a solution for it.
To get the best results, you should consider 4 best practices when designing and creating your challenge.
1. Use Real Problems
Your candidates will be far more motivated and engaged if they feel they are solving an actual problem instead of a question with a catch. Also, by using an actual real-world problem, you can give your candidate a better idea of the types of problems they’ll encounter and have to solve on the job.
2. Take Inspiration From Your Own Company’s Struggles
Related to the above point, instead of finding generic questions from coding challenge websites, it’s far more interesting if you can use problems that either your team has faced or is facing at the moment.
This way, you can be sure you are testing the skills your candidate will need on their day-to-day duties and evaluate if they have a good grasp on the solutions needed to overcome the problems they must face.
3. Establish The Challenge’s Conditions
When testing out several people for a position, it’s important you judge them fairly.
Create a standard test that you hand out to all your candidates and try to provide them with the same conditions as much as possible. This will simplify the process and give you a baseline for you to compare your candidates more easily.
4. Don’t Get Stuck On The Right Answer
Ever heard the expression “It’s not the destination, it’s the journey.”? Coding challenges are much the same. You are, indeed, evaluating the answers of your candidates, but more importantly than that, you want to assess how they do it.
This is especially important in in-person interviews, where you can interact and see the candidate in action. You’ll be able to analyze and evaluate their problem-solving skills and the way they figure out the proposed problem. Coming to a correct answer isn’t as important as having the right mindset to approach the challenge.
Interview Coding Challenge Examples
We’ve already established that custom coding challenges are preferable to generic ones. But even so, we’ll present you with some examples – some even taken from tests done by world-leading tech companies such as Amazon, Microsoft, and Google. Here are some code interview challenges to get inspiration:
Java Coding Challenge Example Questions
- Write a function that checks if a given string has no repeated characters.
- Write a function that given a list with numbers, returns a list with its mean and mode.
- Write a function that upon receiving a string, returns a string with the words reversed.
- Write a function that given a carry weight limit, a list of item weights, and another list of item values, returns the maximum value you can carry while respecting the weight limit.
- Write a function that, given a positive number n, will return the nth number in the Fibonacci sequence.
Python Coding Challenge Example Questions
- Write a function that takes two numbers representing a month and a year, and checks if that month in that year contains a Friday the 13th.
- Write a function that takes two almost equal strings, with the exception of a single character, and returns that differing character.
- Write a function that takes a string and checks if any word in it has duplicate letters.
- Write a function that takes a string and returns another string that contains each character’s hexadecimal value separated by a space.
- Write a function that takes a number, uses its digits to assemble the largest and smallest numbers it can, and returns their difference.
- Write a function that given a list of strings, returns the longest string present.
- Write a function that, given a string, returns the most common character present in it.
- Write a function that takes two strings and finds out if they are anagrams.
- Write a function that, given a string, finds out if it is a palindrome.
- Write a function that given a string with several types of brackets, finds out if their nesting is valid.
Conclusion on Code Interview Challenges
Coding challenges are good methods to evaluate your candidates and see if they can solve problems and the methods and approaches they employ to do so. A good coding challenge can make your candidate selection a far easier and more streamlined process.