How to Start LeetCode from ZERO in 2025

it's 2025 and most top tech company that is still asking lead code style questions in coding interviews but getting started on lead code is harder than ever with over 3,000 problems it's easy to feel overwhelmed and lost how do you even start which problems would you solve and how many problems are enough for coding interviews I will answer these questions and more in this video for context I have solved over, 1500 lead code problems and cleared interviews on multiple big tech companies including Amazon Google and Microsoft in this video I will share everything I have

learned to help you start lead code from zero even if you have never solved a single coding problem before I will share practical tips and resources to help you save time stay focused and build your problem solving skills without feeling overwhelmed you might be wondering why is everyone doing lead code questions is it really necessary to land a software engineering job the short answer is not always there are plenty of startups and smaller companies that focus more on your experience with the specific Tech stacks and the projects you have built they might not even include

lead Cod style questions in their interview process but if your dream is to work at Big tech companies like Amazon Google or Microsoft you need to practice lead Cod style questions since that's what they ask in their interviews which programming language to choose it doesn't really matter a programming language is just a tool once you understand the approach to solving a problem you can implement it in any language in my experience giving interviews unless the job is specifically requires expertise in a certain language you will be fine using any language you are comfortable with the

point is lead code isn't about syntax it's about using the right data structures algorithms and your ability to think critically and solve problems that said if you're new to coding I recommend is starting with python it's beginner friendly and has a simpler syntax if you already know a language stick with it whether it's C++ Java csar JavaScript typescript or go there is no need to switch you don't need to be an expert in your chosen language but you should know basic things like variables and data types for and while Loops eals conditions arrays and strings

functions and classes and input output operations beyond the basics you spend some time learning the built-in libraries for common data structures and algorithms these libraries save time and let you focus on solving the problem rather than reimplementing data structures from scratch for example python has lists dictionaries and sets Java has array list has map and priority queue and C++ offers the STL library with Vector map and set before diving into lead code problems it's good to familiarize yourself with the fundamentals of data structures and algorithms start by understanding B notation and time complexity basic data

structures like arrays strings linklist Stacks cues hash tables and banner trees and fundamental algorithms like sorting techniques Banner search and recursion recursion is particularly important since many problems especially tree and graph related ones rely heavily on it when you are familiar with these topics it becomes much easier to recognize which concept applies to a specific problem you don't need to dive too deeply into every topic of front most of your understanding will develop naturally as you solve problems there are plenty of resources available online to help you get started with data structures and algorithms don't

waste time searching for the perfect resource pick one and start learning here are some resources I personally found quite useful for data structures check out bam F's YouTube channel for visual and detailed explanations for algorithms refer to Abdul bari's YouTube channel and for DSA patterns algo Master IO it's my second Channel where I upload high quality animated tutorials on DSA and Lead code patterns if you a beginner focus on one Topic at a time to avoid feeling overwhelmed for example start with arrays then move on to Strings then progress to more complex topics like link

list hash tables and binary trees once you have learn the basics of a topic and understand how to implement it from scratch it's time to put your knowledge to test solve four to five e problems related to that topic on lead code this will reinforce your learning and build confidence in applying the concepts if you open lead code there are over 3,000 problems that number alone can feel overwhelming so how do you decide which ones to solve we start with easy problems for each topic these are perfect for building confidence and understanding the basics of

problem solving once you comfortable with the easy ones gradually challenge yourself with slightly harder problems that push you beyond your comfort zone remember real growth happens when you constantly challenge yourself don't worry about hard problems at the most coding interviews focus on medium level problems so that's where you should spend the majority of your time L code also provides curated list like the top 100 like problems top 150 interview problems these lists are excellent and I highly recommend solving every problem on them how many problems should I solve there is no magic number but from

my experience 300 well choosen problem is the sweetest spot however it's not about solving just any 300 problems focus on high quality problems that cover the most topics and patterns to make it easier for you I've created a free resource aurated list of the top three under lead code problems organized into 60 topics and patterns that are most commonly asked in coding interviews you can find it at algo master. just head to the practice space you will see a structured list of problems that you can follow from top to bottom here you will find resources

to help you learn the topics ability to track your progress and Mark problems for future revision links to GitHub and YouTube Solutions and the ability to filter problems by keyword difficulty and pattern here are some tips while practicing on lead code take your time don't rush through problems just to increase your problem count instead of focusing on the quanti of problems to solve focus on what you learn from each problem it's far better to deeply understand and solve 50 problems than to superficially solve 500 problems after solving a problem ask yourself why does this solution

work what's the one key inside that made everything else easier also try to make it fun there is a fun in learning to solve coding challenges it's not just about getting a job I was able to solve such a high number of problems because I genuinely enjoyed challenging myself and felt excited whenever my solution got accepted instead of focusing on individual questions focus on identifying underlying patterns that connect similar problem s on lead code you will come across multiple problems that follow a similar pattern once you solve one of them you can apply the same

approach to solve others for example after learning the monotonic stack pattern I was able to solve over 10 similar problems easily here are some of the most important patterns you should know about I made a video covering the 15 most important lead code patterns I learned after solving over 1500 problems you can check it out later on algom master. I have categorized Problems by patterns this makes it easy to focus on one pattern at a time by going through the list you will get to know all the important patterns for coding interviews how to approach

a new problem here is a step-by-step guide first read the problem statement twice the first time focus on getting the big picture what is the problem asking you to do on the second grade pay attention to specific constraint and conditions these small details often provide clues for optimizing Your solution next analyze the input and output examples walk through the input and output is step by step to understand how the problem works I found that many times simply walking through a few examples help me figure out the solution next visualize with pen and paper many problems

especially the ones related to trees and graphs are much easier to understand when you draw them out try to take examples that cover different scenarios and input sizes think about any edge cases that might come up start with a Brute Force approach don't expect to come up with the most optimal solution right away first see if you can solve the problem using a Brute Force approach while it might not be efficient it gives you a baseline to improve upon next optimize your solution once you have a Brute Force solution focus on optimizing it here are

few things to consider leverage unused information look for details you might have missed for instance if the problem is sted array is sorted consider leveraging this to use binary search or a two-pointer approach pre-compute information if certain calculations are repeated multiple times consider pre-computing them use techniques like prefix sums or frequency counts to avoid redundant calculations has tables are widely used in interview questions and this would be at the top of your mind make time versus Space trade offs Sometimes using additional memory example hash tables can speed up your solution do a data structure brainstorm

run through the popular data structures and try to apply each one to the problem at hand also keep it simple avoid over complicating Your solution at every stage ask yourself is there a simpler way to do this this will not only make your solution easier to understand but it will also reduce the chances of Errors during coding and the last develop the habit of analyzing the time and space complexity of every problem you submit how much time should I spend on each problem when your just is starting out even easy problems can take a while

to solve that's completely normal your main goal in the wi should be to focus on learning and understanding the problem deeply real progress happens when you take the time to think make mistakes and Define your approach some problems involve specific tricks or patterns that are hard to figure out unless you have seen them before spending hours on such problems without progress can be counterproductive here is a good rule of thumb give yourself 30 to 60 Minutes of focused effort for each problem if I stay stuck it's okay to look at things or Solutions read the

official solution and try to understand the top oted Solutions on lead code discussion for and don't just move on after viewing the solution try to grasp why the solution works and how you can apply this approach to solve similar problems rewrite the solution from scratch without looking at the code writing it to yourself helps you internalize the approach if you couldn't solve the problem on your first attempt my keep for revision and revisit it after a few weeks revisiting problems helps reinforce your understanding and ensures long-term retention avoid memorization one of the most common mistakes

one that I made myself is memorizing solutions to difficult problems and moving on at first it might seem like a shortcut but in reality it's a big mistake for three main reasons you will quickly forget memorized Solutions without understanding the logic behind them they won't stick in your memory your problem solving the skills won't improve and you will struggle in interviews most interviewer ask variant of problems or follow-up questions and without a deep understanding you won't be able to adapt instead of memorizing focus on understanding the solution even if it takes hours break it down

step by step and ask yourself why does this approach work watch the key inside that simplifies the problem this effort pays off in the long term the deeper your understanding the more confident you will feel explaining your thought process during interviews practice in a timed environment now solving problems during an interview is very different from solving it from the comfort of your home that's why it's a good idea to time box yourself and practice in a timed environment after you have learned the basics and solve 100 to 150 problems for easy problem aim to complete

them in 10 to 15 minutes for medium problems set a timer for up to 30 minutes for hard problems allow yourself up to an hour to take your CTI a step further participate in lead code contest try virtual contest by simulating past lead code contest it's okay if you struggle to solve even one problem easily this is normal the goal is to gain experience solving problems within a time limit when I started participating in contest I could only solve one or two problems but with consistent practice I improve to solving three problems and eventually I

was able to solve all of them in some of the content now getting good at lead code isn't just about learning new Concepts or solving problems it's also about retaining that knowledge over time that's why you should regularly revisit Concepts and problems you have already solved especially the ones you found challenging try to solve those problems again without looking at the solution by practicing consistently and revisiting old problems you will make it much easier to retain what you have learned over time I discuss more about how to effectively revise lead code problems in this video

so make sure to check it out do I need lead code premium if you're just starting out the answer is no you don't need it lead code premium offers two many benefits access to premium only problems and Company specific problem list but all of those you can find easily online for free there are GitHub repositories where you can easily find premium and Company specific problems just do a quick Google search be consistent getting good at lead code takes time some topics might takes weeks or even months to master and that's okay be patient with yourself

and remember it's completely normal to feel stuck or frustrated when working on a top problem or grasping a complex topic if a problem feels too hard take a break then come back to it with a fresh perspective the more you practice the better you will get at solving lead code problem I hope you found this video helpful and gained valuable insights on how to get it started with lead code and use it effectively if you like this video I think you will love my newsletter where I are high quality articles on DSA system design and

interview preparation you can subscribe it at blog. algom master. if you want to learn about the most important lead code patterns I discovered after solving 1583 lead code problems make sure to check out this video thanks for watching and I will see you the next video