47 Coding interview examples with answers (in Python, Java, C++, Etc.)

One of the best ways to prepare for coding interviews is by studying coding mock interview examples. 

There are a lot of free videos out there, but it’s hard to know what language they’re actually using without watching them.

In the article below, we’ve listed the best mock interviews available on YouTube for the most common coding language. 

We hope this list saves you time!

• Python examples
• Java examples
• C++ examples
• Javascript examples
• SQL examples
• Preparation

On a time crunch? You might want to check out our last-minute coding interview prep guide first.

Click here to practice coding interviews with FAANG engineers

1. Python coding interview examples

• Find time in two people’s calendar for a meeting (by Clement Mihailescu)
• Remove islands from a 2D array (by Clement Mihailescu)
• Reverse a LinkedList (by Clement Mihailescu)
• Find the missing element from an array (by interviewing.io)
• Find how many coins you're going to give back as change (by interviewing.io)
• Edit distance string comparison (by interviewing.io)
• Product of array except for self (by Exponent)
• Serialize and deserialize a list of strings (by Exponent)
• Amazon Kindle Object Oriented Design (by freeCodeCamp)
• Detect plagiarized book in library (by freeCodeCamp)
• Design a class to insert, remove and get a random value (by Neetcode)
• Create a unit converter (e.g. km to miles) (by Jane Street)

2. Java coding interview examples

• Binary Search Tree (BSD) successor search (by Keep on Coding)
• Print the left view of a binary tree (by Exponent)
• Find the duplicate number in an array without changing (by Exponent)
• Solve the order statistic of an unsorted array problem (by interviewing.io)
• Find the most frequent integer in an array (by interviewing.io)
• Find the first non repeating character in a string (by Nick White)
• Rotate an image / matrix (by Nick White)
• Find the first duplicate in an array (by Nick White)
• Pancake sorting (by Pramp)
• Create a function to calculate the nth root of a number (by Pramp)
• Find the smallest substring of all characters in an array (by Pramp)
• Find four numbers in an array that sum up to S (by Pramp)

3. C++ coding interview examples

• Determine minimum number of flights to connect all airports (by Clement Mihailescu)
• Determine number of rectangles formed by coordinates on a 2d plane (by Clement Mihailescu)
• Find the apartment that minimzes the farthest distance to places of interest (by Clement Mihailescu)
• Split the pie string into favorite numbers in an array (by Clement Mihailescu)
• Find the minimum number of edges to disconnect a graph (by Keerti)
• Count the number of arrangements in which no guest is wearing the same cap (by Keerti Purswani)
• Find the smallest substring of all characters (by Keep On Coding)
• Find the closest coin on a grid (by interviewing.io)
• Find the missing element from an array (by interviewing.io)

4. Javascript coding interview examples

• Find the longest common subsequence of two strings (by interviewing.io)
• Create a regular expression evaluator (by interviewing.io)
• Determine if a word is in a dictionary (by DonTheDeveloper)
• Determine the point value for a word in a set of titles (by DonTheDeveloper)
• Decrypt / Encrypt a message (by Pramp)
• Find the smallest non-negative number not in an array (by Pramp)
• Capitalize every other letter in a string (by Tech with Nader)
• Multiple smaller React questions (by Ben Awad)
• Multiple smaller JS questions (by Ben Awad)

5. SQL coding interview examples

• Create a daily report to track campaign performance (by Jay Feng)
• Get the daily distribution of the number of conversations in a messaging app (by Jay Feng)
• Calculate the average order size (by DataInterview)
• Measure user churn (by DataInterview)
• Segment influencers (by DataInterview)
• Calculate the revenue of each department (by Exponent)
• Find employees who earn more than their manager (by Exponent)
• Count the number of successful posts by user type (by Exponent)

6. How to prepare for coding interviews

One of the main challenges of coding interviews is that you have to communicate what you are doing as you are doing it. Having to think, code, and communicate your thoughts to the interviewer all at the same time is not easy.

With that in mind, don't let the first interview you do be the real thing. Instead, we highly recommend getting some mock interviews under your belt. 

6.1 Practice with peers

If you have friends or peers who can do coding mock interviews with you, that's an option worth trying. It’s free, but be warned, you may come up against the following problems:

• It’s hard to know if the feedback you get is accurate
• They’re unlikely to have insider knowledge of interviews at your target company
• On peer platforms, people often waste your time by not showing up

For those reasons, many candidates skip peer mock interviews and go straight to mock interviews with an expert. 

6.2 Practice with experienced coding interviewers

In our experience, practicing real coding interviews with experts who can give you company-specific feedback makes a huge difference. If you're still canvassing expert coaching services for coding interviews, check out our guide to the best coding interview coaching websites.

Or you can skip straight to finding a coding interview coach here, so you can:

• Test yourself under real interview conditions
• Get accurate feedback from a real expert
• Build your confidence
• Get company-specific insights
• Save time by focusing your preparation

Landing a job at a big tech company often results in a $50,000 per year or more increase in total compensation. In our experience, three or four coaching sessions worth ~$500 make a significant difference in your ability to land the job. That’s an ROI of 100x!