Software engineering interviews can be daunting, especially when they involve algorithmic questions which are a staple at many top tech companies. This blog post will guide you through getting started with your interview preparation using LeetCode, a popular platform for practicing coding problems.

We'll cover why algorithmic interviews are so prevalent, the benefits of starting with easier problems, and a strategic approach to gradually increasing your proficiency and confidence.

Understanding Algorithmic Interviews

Why Are Algorithmic Interviews Common?

Algorithmic interviews test a candidate's problem-solving skills through technical questions that require the application of data structures and algorithms. The reason these types of questions are so popular is that they help interviewers assess a candidate’s coding ability, logical thinking, and even their performance under pressure, which are crucial attributes for a software engineer.

These interviews often involve questions that range from simple array manipulations to complex graph-based problems. The interviewer is not just interested in the correct answer but also in the candidate's approach to solving the problem, their ability to optimize the solution, and how they handle edge cases.

Getting Started with LeetCode

What is LeetCode?

LeetCode is an online platform that offers a vast array of coding problems designed to mirror the types of questions frequently asked in software engineering interviews. With a mix of over 1,500 questions, categorized by difficulty (Easy, Medium, and Hard), LeetCode serves as an essential tool for anyone preparing for technical interviews.

Why Start with Easy Problems?

Starting with easy problems can have multiple benefits:

• Build Confidence: Easy problems help in building confidence with simpler concepts before moving on to more complex algorithms.

• Fundamentals First: They ensure that your foundational knowledge of data structures and algorithms is solid. Many easy problems involve basic array manipulations, binary searches, or simple string manipulations.

• Stress-Free Learning: Starting easy can make the learning process less intimidating and more enjoyable. It’s like warming up before a rigorous workout.

Effective Strategies for Using LeetCode

1. Set Realistic Goals

Before diving into coding, set clear, achievable goals. Decide how many problems you want to solve each week and what topics you want to cover. This helps in maintaining a steady pace without feeling overwhelmed.

2. Understand Before You Solve

For each problem, thoroughly read and try to understand the problem statement and constraints. Before coding, think about your approach, jot down your thoughts, and even discuss these with peers or mentors if possible.

3. Start Coding

Once you have a solid approach, start coding. Initially, focus on getting a correct solution rather than the optimal one. As you improve, start refining your solutions to make them more efficient.

4. Review and Reflect

After solving a problem, review your solution and compare it with others in the LeetCode community. This can provide insights into different ways to approach the same problem. Reflect on what you learned from this problem, and how you can apply this knowledge to future problems.

5. Gradually Increase Difficulty

Once you feel comfortable with a good number of easy problems, start incorporating medium difficulty problems into your practice. This should be a gradual process. For every few easy problems, try solving a medium one. This ratio can change as you become more comfortable.

6. Mock Interviews

LeetCode offers mock interviews that are structured to mimic real-life interview scenarios. These are timed and cover a range of topics. Engaging in these can help you manage time effectively and experience the pressure of a real interview.

Additional Tips

• Daily Practice: Make it a habit to solve at least one problem a day. This keeps the concepts fresh in your mind.

• Discuss Solutions: Join a community or group that focuses on coding interviews. Discussing solutions and thought processes can open up new perspectives and learning opportunities.

• Focus on Weak Areas: It’s natural to gravitate towards problems that you’re comfortable solving. However, for a balanced preparation, focus equally on areas where you are weak.

Easy Problems

To further aid your preparation, I will be including a list of the best easy problems to start with, ensuring you have a clear path from the beginning. These are problems that I use to study and I written a helpful guide for each of them.

• Two Sum - LeetCode | Solution Guide

• Valid Parentheses - LeetCode | Solution Guide

• Merge Two Sorted Lists - LeetCode | Solution Guide

• Best Time to Buy and Sell Stock - LeetCode | Solution Guide

• Valid Palindrome - LeetCode | Solution Guide

• Invert Binary Tree - LeetCode | Solution Guide

• Valid Anagram - LeetCode | Solution Guide

• Binary Search - LeetCode | Solution Guide

• Flood Fill - LeetCode | Solution Guide

• Lowest Common Ancestor of a Binary Search Tree - LeetCode | Solution Guide

• Balanced Binary Tree - LeetCode | Solution Guide

• Linked List Cycle - LeetCode | Solution Guide

• Implement Queue using Stacks - LeetCode | Solution Guide

• First Bad Version - LeetCode | Solution Guide

• Ransom Note - LeetCode | Solution Guide

• Climbing Stairs - LeetCode | Solution Guide

• Longest Palindrome - LeetCode | Solution Guide

• Reverse Linked List - LeetCode | Solution Guide

• Majority Element - LeetCode | Solution Guide

• Add Binary - LeetCode | Solution Guide

• Diameter of Binary Tree - LeetCode | Solution Guide

• Middle of the Linked List - LeetCode | Solution Guide

• Maximum Depth of Binary Tree - LeetCode | Solution Guide

• Contains Duplicate - LeetCode | Solution Guide

• Backspace String Compare - LeetCode | Solution Guide

• Counting Bits - LeetCode | Solution Guide

• Same Tree - LeetCode | Solution Guide

• Number of 1 Bits - LeetCode | Solution Guide

• Longest Common Prefix - LeetCode | Solution Guide

This article was inspired by the popular study guide, Grind 75, a tool meticulously crafted to streamline the preparation for technical interviews by focusing on 75 key problems considered most effective for mastering the skills required to excel in interviews.

Grind 75 simplifies the overwhelming landscape of potential interview questions into a manageable set, ensuring comprehensive coverage of essential topics. By following a similar philosophy, this guide aims to provide a structured pathway through LeetCode, starting with simpler problems and gradually progressing to more complex challenges, making your preparation journey both focused and efficient.

Conclusion

Starting your journey of preparing for software engineering interviews using LeetCode with easy problems is a strategic approach to build your skills progressively. It helps lay down a strong foundation, builds your confidence, and gradually prepares you for more challenging problems.

Remember, consistency is key. Regular practice, combined with a strategic approach to learning and problem-solving, will make you well-prepared for tackling algorithmic interviews.

So start coding, keep learning, and ace those interviews!