The Ultimate LeetCode Guide to Technical Interviews

Whether you dream of a job at Google or try to crack the interview at a promising startup, tackling coding difficulties effectively is crucial to making an impression. This article will walk you through essential strategies, problem-solving techniques, and practical LeetCode guide tips to help you maximise your interview preparation time. 

Why is LeetCode a crucial (and marketable) skill? 

One popular resource for preparing coding assignments specific to technical interviews is LeetCode. It is the preferred tool for interview preparation due to its extensive library of challenges, which cover topics like algorithms, data structures, and system design and range in difficulty from easy to severe.

However, LeetCode’s success is about something other than employing brute force or resolving arbitrary problems. It entails creating a systematic, successful plan that refines your problem-solving skills and reinforces fundamental concepts in computer science. Familiarising yourself with LeetCode is essential because most tech giants frequently use it in interviews. Being comfortable with the platform can really boost your chances of making it through those nerve-wracking coding rounds.

Step 1: Understand the basics 

Before entering LeetCode, ensure you have a solid understanding of data structures and algorithms. If you have a firm grasp of these, it could be more accessible to solve problems effectively. Here is a quick rundown of the main ideas: 

Data structures: Arrays, linked lists, stacks, queues, trees (binary, binary search, AVL, etc.), graphs, heaps, and hash tables are the main ones to focus on. One typical method of testing these is through interviews. 

Algorithms: Sorting (merge sort, quicksort), searching (binary search), depth-first search (DFS), breadth-first search (BFS), backtracking, greedy algorithms, recursion, and dynamic programming. 

Big-O notation: Make sure you understand the complexities of time and space because this is a commonly requested interview topic. You should explain how your solutions compromise performance. 

Once you comprehend them, you’re ready to plunge into LeetCode. 

Step 2: Start with easy problems 

When you first join LeetCode, it could be tempting to tackle the medium or challenging problems immediately. Still, it’s better to start with the easier ones to build confidence and familiarise yourself with the platform. You can practise structuring your code and paying close attention to the problem descriptions by working through the easy problems, even though they are sometimes complicated. 

Focus on comprehending the problem-solving process rather than attempting to solve as many problems as possible. Note the methodologies and trends, but pay attention to the basics, which are sometimes stepping stones to more complicated issues. 

Pro tip: Solve problems with basic data structures, including strings, arrays, and linked lists. Use LeetCode’s Discuss section to see how others have addressed the issue. This makes it easier to understand multiple approaches to the same problem. 

Step 3: Create a strategy 

Once you’ve solved a few easy problems, it’s time to take on more challenging ones. Planning is crucial in this situation. Here’s how to structure your problem-solving strategy: 

Decide on daily or weekly goals: Decide how many problems you wish to solve every day or every week. Remaining steady is preferable to resolving all the issues at once and then taking a long rest. 

Combine issue challenges: Do not limit yourself to easy or moderate tasks. Mix them up. For instance, aim for 70% medium, 20% easy, and 10% challenging problems. This will allow you to push yourself. 

Pay attention to specific topics: LeetCode allows you to sort issues by subject if you have trouble with dynamic programming practice problems that fit into that category until you are comfortable with it. 

Pro tip: LeetCode includes company-specific tags. By filtering difficulties according to those categories, you can view questions asked in interviews with companies like Google, Microsoft, or Amazon. 

Step 4: Practical approach to solving problems 

The secret to mastering LeetCode is your problem-solving skills. This is a systematic way to fix any coding problem: 

• Carefully read the problem: Take your time reading the description. Small facts in the scenario often change your approach. 
  
• Identify the input and output: Look for edge circumstances, such as empty arrays or significant inputs. Ask yourself, “What are the possible pitfalls?” 
  
• Plan your approach: Before writing code, consider the best approach to solving the issue. Will a brute-force method work, or is there a more optimised algorithm? 
  
• To help you understand the logic, write pseudocode before creating code. It is advantageous to cultivate this practice, especially when handling more complex problems. 
  
• Write code that is easy to read and comprehend to build programs quickly. Many companies assess your solution’s accuracy and code’s readability. 
  
• Verify your response: Test not only against other scenarios but also against edge cases. Verify that your code is capable of handling inputs of various sizes. 

Step 5: Review your responses 

Once a problem has been resolved, keep going. Look at your solution to see if it can be made more effective. LeetCode provides runtime and memory utilisation statistics that you can use to compare your solution to others. While working with large input sizes, minimise the temporal complexity of your solutions. 

Step 6: Take mock interviews

Many applicants need help to apply their LeetCode expertise in practical interview settings. To address this gap, LeetCode offers a feature called “Mock Interview.” To replicate an actual technical interview situation, you are required to solve problems within time constraints. 

Participating in mock interviews may improve your communication skills, which are essential during the interview process. You can also get used to the pressure of timed interviews. They also give you feedback that highlights your areas for development. 

Step 7: Learn from mistakes 

Don’t give up if you can’t solve a problem right away. Technical interviews demand both skill and persistence, much like competitive programming. Every issue that remains unsolved offers a chance to learn. Take a close look at the solutions, determine why your plan didn’t work, and focus on improving. 

Step 8: Perform frequent valuations 

Finally, practising new problems is as important as reviewing your studies. It would help if you went over the issues you have faced in the past. By doing this, you’ll be able to grow from your errors and avoid repeating them. 

Distilled 

Mastering LeetCode is a marathon, not a sprint. It’s about building a skill set that will help you in interviews and beyond. Stay consistent, challenge yourself, and remember to take breaks. Happy coding, and good luck out there.