How to Start Leetcode (as a beginner)

Summary

In this video, the speaker shares insights from solving over 1500 coding problems and clearing interviews at tech giants like Amazon, Google, and Microsoft. They guide viewers on how to start with LeetCode, choose a programming language, and the importance of understanding data structures and algorithms. They recommend starting with easy problems, focusing on medium difficulty for interviews, and learning from each problem rather than just the quantity. Tips on approaching new problems, using resources like YouTube and books, and practicing in a timed environment are also provided.

Takeaways

• 😀 You can get a software development job without coding on LeetCode, but it's beneficial for interviews at big tech companies like Amazon, Google, and Microsoft.
• 🔍 There's no one 'right' programming language for coding interviews; popular languages like C++, Java, Python, or JavaScript are all acceptable.
• 👶 For beginners in coding, Python is recommended due to its simplicity and ease of learning.
• 🌟 Understanding basic programming concepts like loops, conditionals, functions, and basic input/output operations is crucial, regardless of the language you choose.
• 📚 To learn data structures and algorithms, resources like William Fiset's YouTube channel and books like 'Data Structures and Algorithms Made Easy' are helpful.
• 🎯 Start with problems by topic on LeetCode to deepen your understanding and learn when to use specific data structures or algorithms.
• 🚀 Focus on medium-level problems, as these are typically what you'll encounter in interviews, rather than getting stuck on hard problems early on.
• 🤔 When starting, aim to solve 300 to 400 problems to build a strong foundation, focusing on understanding rather than just the quantity.
• 🕒 Spend at least 30 to 60 minutes on a problem before looking at solutions; understand and implement the solution to reinforce learning.
• 📈 Learn to recognize patterns in problems on LeetCode, as many follow similar approaches, which can speed up your problem-solving.
• 💡 Memorizing solutions is not effective; understanding the logic and being able to explain your thought process is key for interviews.

Q & A

Why is practicing on LeetCode recommended for job interviews at big tech companies?

Practicing on LeetCode is recommended because it's an effective platform to prepare for technical interviews at big tech companies like Amazon, Google, and Microsoft, where coding challenges are a common part of the hiring process.

Can you get a software development job without doing LeetCode?

Yes, it's possible to get a software development job without doing LeetCode, especially at startups that may not focus on such coding challenges. However, for roles at big tech companies, LeetCode practice is beneficial.

What programming language should one use for LeetCode and interviews?

There is no single 'right' language; any popular language like C++, Java, Python, or JavaScript is suitable. For beginners, Python is recommended due to its simplicity and ease of learning. It's best to stick with a language you're comfortable with and understand its basic syntax and concepts.

Does the choice of programming language matter in big tech interviews?

No, as long as it's a well-known language, the choice doesn't matter much because a programming language is just a tool, and problems can be solved using multiple languages.

What should a beginner know before starting to solve LeetCode problems?

A beginner should have a basic understanding of computer science fundamentals, including time and space complexity, and be familiar with fundamental data structures and algorithms. Concepts like loops, conditionals, functions, and basic input/output operations are essential.

How can one learn data structures and algorithms effectively?

One can learn through various online resources, such as YouTube channels like William Fiset, which provides visual explanations, or books like 'Data Structures and Algorithms Made Easy' by Nariman Gulam and 'Cracking the Coding Interview' by Gayle Laakmann McDowell.

How should a beginner approach solving LeetCode problems?

Beginners should start by solving problems by topic to gain a deeper understanding. Start with easy problems and gradually move to more challenging ones. Focus on medium-level problems as they are most commonly encountered in interviews.

How many problems should one aim to solve on LeetCode?

The number of problems varies based on the individual's level. For beginners, solving 300 to 400 problems is generally sufficient. The focus should be on understanding rather than just increasing the count.

How does one effectively approach a new LeetCode problem?

Take time to understand the problem statement, expected input/output, and start with a brute force solution. Then, work on optimizing it by reducing time and space complexity. Plan your approach before coding and develop the habit of analyzing the complexity of your solutions.

When should one look at the solution if stuck on a LeetCode problem?

If you're stuck, give at least 30 to 60 minutes of focused effort. If still stuck, look at hints or solutions. It's important to understand and try to implement the solution yourself, not just move on.

How can one practice solving problems like they are in an interview?

Practicing in a timed environment is crucial. Using tools like the LeetCode timer or participating in LeetCode contests can simulate the interview experience. It's about gaining experience solving problems within a time limit.

Is a LeetCode premium subscription necessary for beginners?

Not necessarily. While premium offers access to exclusive problems and visual solutions, these can often be found for free online. A premium subscription may be more beneficial for those looking for additional resources or a more structured learning path.

Outlines

00:00

💻 Getting Started with LeetCode

The speaker, having solved over 1500 LeetCode problems and cleared interviews at tech giants like Amazon, Google, and Microsoft, shares insights to ease the viewers' coding journey. They outline a strategy for starting from scratch with LeetCode, addressing common questions about its necessity for software development jobs, especially for big tech companies. The speaker clarifies that while startups might not require LeetCode proficiency, it's essential for interviews at larger corporations. They also discuss the choice of programming language, recommending Python for beginners due to its simplicity and readability, and emphasize the importance of understanding basic syntax and concepts across popular languages like C++, Java, and JavaScript.

05:01

📚 Mastering Data Structures and Problem-Solving Strategies

The speaker advises new coders to grasp computer science fundamentals such as time and space complexity, and basic data structures and algorithms before tackling LeetCode problems. They highlight the significance of understanding big O notation for algorithm efficiency and recommend resources like William Fiset's YouTube channel and books like 'Data Structures and Algorithms Made Easy' by Nariman Kumar and 'Cracking the Coding Interview' by Gayle Laakman McDowell. For beginners, the speaker suggests starting with easy problems by topic to deepen understanding and learn when to apply specific data structures or algorithms. They also discuss the importance of challenging oneself with progressively harder problems and the value of learning from each problem solved, rather than focusing on the quantity of problems attempted.

Keywords

💡Lead Code

Lead Code refers to the practice of solving coding problems that are typically asked during technical interviews, often found on platforms like LeetCode. In the video, the speaker emphasizes the importance of Lead Code practice for those aspiring to work at big tech companies like Amazon, Google, and Microsoft. The script mentions solving over 1500 Lead Code problems and using the platform to prepare for interviews.

💡Data Structures

Data structures are specialized formats for organizing, processing, and storing data. The video script suggests that having a foundational understanding of data structures like arrays, strings, binary trees, linked lists, stacks, queues, and hashmaps is crucial before starting with Lead Code problems. These structures are essential for solving coding challenges efficiently.

💡Algorithms

Algorithms are step-by-step procedures to solve problems. The script highlights the need to learn basic algorithms such as string searching and recursion. Understanding algorithms is key to improving coding efficiency and is a core part of Lead Code preparation, as it helps in developing solutions for coding challenges.

💡Big O Notation

Big O Notation is a mathematical notation that describes the time complexity of an algorithm, indicating the upper bound of time an algorithm takes to run. The video script mentions learning Big O Notation to understand why an algorithm might be slow and to improve it, which is vital for optimizing solutions during Lead Code challenges.

💡Programming Language

A programming language is a formal language comprising a set of instructions used to create software. The speaker in the video clarifies that there is no 'right' programming language for Lead Code, but popular ones like C++, Java, Python, or JavaScript are recommended. The choice of language should be based on familiarity and the language's popularity in the industry.

💡Interview Preparation

Interview preparation in the context of the video refers to the process of getting ready for technical interviews, particularly those at big tech companies. The script provides insights on how to use Lead Code to prepare for such interviews, including the types of problems to solve and the importance of understanding data structures and algorithms.

💡Problem Solving

Problem solving is the process of finding solutions to problems. The video script discusses various strategies for solving Lead Code problems, such as starting with a brute force solution and then optimizing it. This approach is crucial for improving problem-solving skills, which are essential for both Lead Code challenges and technical interviews.

💡Time and Space Complexity

Time complexity refers to the amount of time an algorithm takes to run, while space complexity refers to the amount of memory it uses. The script emphasizes the importance of analyzing the time and space complexity of submitted solutions, as interviewers often focus on finding optimal solutions.

💡Practice

Practice, as mentioned in the video, is the act of repeatedly working on Lead Code problems to improve skills. The speaker advises solving 300 to 400 problems for beginners and focusing on learning from each problem rather than just increasing the problem count. Practice is key to mastering Lead Code challenges.

💡Patterns

Patterns in the context of the video refer to common approaches or strategies used to solve certain types of coding problems. The script suggests learning these patterns to solve multiple problems efficiently. Identifying and understanding patterns can significantly reduce the time spent on solving similar problems.

💡Memorization

Memorization is the act of committing information to memory. The video script advises against memorizing solutions to difficult problems, as it does not improve problem-solving skills and can be detrimental during interviews. Instead, the speaker encourages understanding and applying concepts, which is more beneficial for long-term retention and interview scenarios.

Highlights

The speaker has solved over 1500 LeetCode problems and cleared interviews at Amazon, Google, and Microsoft.

LeetCode is recommended for preparing for interviews at big tech companies like Amazon, Google, or Microsoft.

One can get a software development job without LeetCode, especially at startups.

There is no 'right' programming language for LeetCode; any popular one like C++, Java, Python, or JavaScript will do.

Python is recommended for beginners due to its simplicity and ease of use.

Understanding basic syntax and concepts like loops, conditionals, functions, and I/O operations is essential.

Learning common data structures and libraries, such as STL in C++ or collections in Java, is beneficial.

The choice of programming language does not matter in big tech interviews as long as it's well-known.

Before solving LeetCode problems, one should understand computer science fundamentals like time and space complexity.

Familiarity with basic data structures and algorithms is necessary before starting LeetCode.

William Fiset's YouTube channel and 'Data Structures and Algorithms Made Easy' by Nariman Kumar are recommended learning resources.

Beginners should start solving LeetCode problems by topic to gain a deeper understanding.

Focusing on medium-level problems is recommended as they are commonly encountered in interviews.

For experienced coders, curated lists like 'LeetCode 75' or 'Top Interview 150' are suggested.

It's better to thoroughly understand and solve fewer problems than to solve many without much understanding.

When approaching a new problem, start with a brute force solution and then optimize.

It's important to analyze the time and space complexity of every problem submitted.

If stuck on a problem, give it at least 30 to 60 minutes before looking at hints or solutions.

Learning patterns is more efficient than focusing on individual questions on LeetCode.

Memorizing solutions is not recommended; understanding the concepts is crucial for interviews.

Practicing in a timed environment, like LeetCode contests, is essential to simulate interview conditions.

LeetCode premium is not necessary for beginners as most of its benefits can be found for free online.

The speaker shares their coding journey and offers to make videos on requested topics.

Transcripts

having solved more than 1500 lead code

problems and having cleared interviews

at companies like Amazon Google and

Microsoft there are things I have

learned that I want to share with you in

this video to make your journey easier

and less painful today I will explain

how I would use lead code if I were

starting from scratch I will answer most

common questions people have while

starting their lead code journey and say

resources you can use to become more

productive while practicing question why

do I even need to do lead code can't I

get a software development job without

lead code well the answer is yes you can

and get a software development job

without lead code there are many

startups that don't ask these type of

questions but if your goal is to work at

Big tech companies like Amazon Google or

Microsoft you would need to practice on

lead code since it's the best platform

to prepare for their interviews question

which programming language I should use

for lead code and interviews many people

get confused when deciding which

programming language to use well there

is no right programming language as long

as it's a popular one like C++ Java

python or JavaScript if you're new to

coding and don't know any programming

language I would recommend going with

python since it's easy to get started

with and has a simple syntax if you

already know a programming language well

stick with it you don't need to be an

expert but you should understand basic

syntax and Concepts like Loops

conditional functions and basic input

and output operations most programming

languages come with inbu support for

common data structure and libraries for

example the STL in C++ and the collect

library in Java so you spend some time

learning these it will make your journey

a lot easier question does choice of

programming language matter in big Tech

interviews the answer is no as long as

it's a well-known programming language

the reason it doesn't matter is because

a programming language is just a tool

and you can solve the same problem using

multiple programm languages I started

using C++ in the beginning then switched

to Python and finally to Java since most

of my industry experience was in Java

question I am new to data structures and

algorithms how do I learn this before

solving your first lead quote problem

you should have some idea about computer

science fundamentals such as time and

space complexity as well as basic data

structures and algorithms you don't need

to go very deep since most of the

learning will happen while solving

coding challenges but make sure you are

familiar with how to calculate time and

space complexity of an algorithm using

big or notation learning big on notation

will help you improve your algorithms

and better understand why your algorithm

may be running slowly once you have a

grasp of big on notation familiarize

yourself with fundamental data

structures like arrays strings binary

trees link list St Stacks cues and

hashmap and learn basic algorithms such

as sting searching and recursion you

don't need to know advanced concepts but

it's important to know how to implement

basic concepts in your preferred

programming language to learn these

topics you can find many resources

online one YouTube channel that I found

particularly helpful for learning data

structures is William faet they have a

data structure playlist where important

data structures are explained visually

if you like reading books then I

recommend reading data structures and

algorithms Made Easy by narima kumachi

and cracking the coding interview by gay

lakman McDow question there are

thousands of problems on lead code which

ones to solve if you a beginner start by

solving problems by topic this approach

will help you gain a deeper

understanding of each topic and learn F

data structure or algorithm to use for a

specific problem for each Topic start

with easy problems once you can

comfortably solve easy ones slowly start

challenging yourself with problems which

are slightly outside your comfort zone

you must constantly challenge yourself

to get better don't worry about hard

problems in the beginning in most

interviews you will encounter medium

level problems so Focus most of your

time on those the types of problems ask

in interviews differs from company to

company and it depends on the role you

are interviewing for in general backend

roles tend to ask harder questions

compared to front roles and Fang

companies ask more difficult questions

compared to startups for senior roles

experience and system design matter more

than lead code questions if you already

have some experience with lead code or

similar platforms you can choose curated

list of problems like need Cod 75 or top

100 lik or top interview 150 questions

on lead code don't spend too much time

on highly disliked questions they will

drain your energy and demotivate you

sometimes you may come across a problem

that is tagged as easy but it still

proves to be difficult to solve don't

get discouraged this is all part of the

learning process and sometimes lead code

doesn't do a good job of classifying the

difficulty level of the problem avoid

jumping between problems too quickly

give each problem sufficient time and

effort after every problem you solve ask

yourself what is one thing knowing which

made everything else easier question how

many problems should I solve this is

subjective and depends on the level at

which you are at if you are new you

would need to solve more problems in

general 300 to 400 problems should be

good enough a mistake I made in the

beginning was rushing to increase my

problem count without spending enough

time on each problem instead of focusing

on the quantity of problems you solve

focus on what you learn from each

problem it is much better to thoroughly

understand and solve 20 problems than to

solve 100 problems without much

understanding also try to make it fun

there's 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

enjoyed challenging myself and felt

excited whenever my solution was

accepted question how do I approach a

new problem take some time to understand

the problem statement and the expected

in input and output patterns write it

down on paper if it helps start with

brute for solution and then work on

optimizing it think about how you can

improve the algorithm or reduce the time

and space complexity plan your approach

before coding coding is easy Once you

know what you are going to write so

before writing a single line of code

make sure you understand what exactly

you are going to write that's one reason

why programming language doesn't matter

much because it doesn't take too long to

implement a solution once you have a

good idea on what to write develop the

habit of analyzing the time and space

complexity of every problem you submit

interviewers focus a lot on finding

Optimal Solutions and may ask about the

complexity of your code it is a good

practice to test your code with a small

inputs including edge cases question if

I'm stuck with a problem when should I

look at the solution give at least 30 to

60 Minutes of focused effort to a

problem if you still stuck look at hints

and solutions don't spit too long on one

problem read the official solution and

try to understand the top Ed Solutions

you can check out this extension called

lead code video Solutions which allows

you to watch solution videos directly on

the problem page don't just move on

after being the solution try to

implement it yourself also since you

were to solve this problem on your first

attempt it's a good idea to market for

revision and revisit this problem after

a few weeks question how do I solve more

problems in less time the answer is to

learn patterns instead of focusing on

individual questions concentrate on

identifying patterns on lead code you

will come across multiple problems that

follow a similar pattern once you know

how to to solve one of them you can

apply the same approach to solve others

for example after learning this serving

pattern I was able to successfully solve

more than 20 sting questions using the

same approach I have created this GitHub

repository to list common lead quote

patterns from different articles you can

find the link in the description

question should I memorize solution to

difficult problems when I was a beginner

I used to memorize the solution to the

difficult problems and move on I later

realized that it was a big mistake

memorizing Solutions does not improve

your problem solving skills and it is

not helpful during interviews because

the interviewer might ask a variant of

the problem or a follow-up question

inform is a retain Pro understanding is

more likely to stay with you long term

during interviews it is important to

explain your thought process if you have

only memorized the solution you may

struggle to convince the interviewer why

your solution will work question how do

I practice like I am in an interview

solving a problem during an interview is

very different from solving it at home

sitting at your sofa that's why you need

to practice in a timed environment

there is a lead code extension called

lead code timer that you can use to time

yourself while practicing I highly

recommend participating in lead code

contest as they provide the best way to

practice in a timed environment don't

worry if you struggle to solve even one

problem in the beginning the whole point

is to gain some experience solving

problems within a time limit when I

started giving contest I was able to

solve only one to two problems but with

more practice I was able to solve three

problems and sometimes even all of them

question do I need lead code premium if

you are just starting out you don't need

to purchase lead code premium there are

three main benefits you get as a premium

Member First is you can unlock premium

only problems second you can access the

company specific problems and the third

you can access Visual solution to some

of the problems but all of these you can

find easily online for free if you need

visual explanation of any problem simply

type lead code on YouTube followed by

the problem number no matter what

problem it is you will find plenty of

high quality videos explaining its

solution if you want to learn more about

my coding journey and how I went from

zero to cracking interviews at multiple

big tech companies you can check out

this video if you have any questions or

want me to make a video on another topic

let me know in the comments I wish you

all the best thanks for watching and I

will see you in the next video