Preparing for technical coding interviews can be challenging, but with the right approach, you can improve your chances of success.

If you have just started preparing for an interview, always start with the basics. It is essential to learn the basics of programming concepts, data structures, and algorithms. You can start with popular programming languages such as Python, Java, or C++. There are many online courses, tutorials, and books available that can help you get started.

Practice coding problems to prepare for coding interviews. The best way to do this is by solving coding challenges and questions on websites such as LeetCode, HackerRank, and CodeSignal.

Study common interview questions. There are several questions that are asked in technical coding interviews. Make sure you study these questions and practice answering them.

Practice mock interviews with friends or colleagues. This will help you get a feel for the interview process and help you identify areas where you need improvement.

Keep yourself updated with the latest trends in technology and coding. Follow coding blogs, read technical articles, and participate in online coding communities.

Lastly, it is crucial to stay calm and confident during the interview. Take your time to understand the problem, think through the solution, and communicate your thought process to the interviewer.

What are some gotchas I should be aware of?

When preparing for technical coding interviews, there are a few things to keep in mind that can trip you up if you’re not careful. Here are some gotchas to be aware of:

  1. Not practicing enough: One of the most common mistakes that beginners make is not practicing enough. Make sure you spend enough time practicing coding problems and familiarizing yourself with the interview format.
  2. Focusing too much on memorization: It’s important to understand the underlying concepts and principles of programming and algorithms, rather than just memorizing solutions to specific problems. Don’t rely on memorization alone as it may not help in solving new and unfamiliar problems.
  3. Not communicating effectively: Technical coding interviews are not just about writing code, but also about effectively communicating your thought process to the interviewer. Make sure you articulate your reasoning and steps as you work through the problem.
  4. Ignoring edge cases: Another common mistake is not considering edge cases, which are inputs that are unusual or unexpected but can affect the behavior of the program. Make sure you test your code with various inputs to ensure it works for all cases.
  5. Not asking questions: Don’t be afraid to ask clarifying questions if you’re not sure about something. It’s better to ask and clarify than to make assumptions that could lead to incorrect solutions.
  6. Not being aware of time: Time management is crucial in technical coding interviews. Make sure you’re aware of how much time you have and manage it effectively to complete the task.

What topics should I cover if I am a beginner?

Technical coding interviews can cover a wide range of topics and questions, but here are some common topics that you should cover when preparing:

  1. Data structures: Questions on data structures such as arrays, linked lists, stacks, queues, trees, graphs, and hash tables are very common in coding interviews.
  2. Algorithms: Understanding common algorithms such as sorting, searching, and graph traversal algorithms, is essential. You should be able to implement them and explain their time and space complexity.
  3. Problem-solving skills: Coding interviews typically involve solving algorithmic problems. You should practice breaking down complex problems into smaller subproblems, identifying patterns, and developing an algorithm to solve them.
  4. Object-oriented programming: If the language you’re using is object-oriented, you should be familiar with concepts such as inheritance, encapsulation, and polymorphism.
  5. System design: In some interviews, you may be asked to design a system, such as a web application or a distributed system. You should be able to discuss system architecture, scalability, and trade-offs.
  6. Debugging skills: Debugging is an essential skill for any developer. You should be able to read and understand error messages, and use debugging tools to identify and fix issues in your code.
  7. Code optimization: Interviewers may ask you to optimize your code for time or space complexity. You should be able to identify bottlenecks in your code and propose alternative solutions.
  8. Soft skills: While technical skills are crucial, interviewers also look for soft skills such as communication, collaboration, and problem-solving approach.

Easy Coding Interview questions for beginners

Leetcode two sum coding problem: Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target

The solution loops through the array nums and uses a dictionary (Python) or map (Ruby, Java, JavaScript) to store the indices of the numbers we have seen so far.

For each num, we calculate its complement complement = target - num and check if it exists in the dictionary/map. If it does, we return the indices of the complement and the current element as an array.

If the complement does not exist in the dictionary/map, we add the current element and its index to the dictionary/map.

We raise an exception if we reach the end of the loop without finding a solution. The time complexity of this solution is O(n) because we loop through the array once, and each dictionary/map lookup takes constant time on average.

The space complexity is also O(n) because we need to store the indices of the numbers in the dictionary/map.

# pseudocode
function twoSum(nums, target):
    dict = {}
    for i, num in enumerate(nums):
        complement = target - num
        if complement in dict:
            return [dict[complement], i]
        dict[num] = i
    raise ValueError("No two sum solution")